<PAGE>

                                                                   EXHIBIT 10.13

================================================================================

                                [LOGO OF CHASE]

                               CREDIT AGREEMENT



                                  dated as of


                              September 29, 2000

                                     among

                             PURE RESOURCES, INC.


                           The Lenders Party Hereto



                           THE CHASE MANHATTAN BANK,
                            as Administrative Agent

                                      and

                          FIRST UNION NATIONAL BANK,
                             as Syndication Agent

                          __________________________

                          CHASE SECURITIES INC., and
                         FIRST UNION SECURITIES, INC.
                                 as Arrangers

                     $250,000,000 364-Day Revolving Credit


================================================================================
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                           Page
                                                                                           ----
<S>                                                                                        <C>
ARTICLE I
         Definitions......................................................................  -1-
         -----------
         SECTION 1.01.  Defined Terms.....................................................  -1-
                        -------------
         SECTION 1.02.  Terms Generally................................................... -15-
                        ---------------
         SECTION 1.03.  Accounting Terms; GAAP............................................ -16-
                        ----------------------

ARTICLE II
         The Credits...................................................................... -16-
         -----------
         SECTION 2.01   Commitments....................................................... -16-
                        -----------
         SECTION 2.02   Borrowing Requests................................................ -17-
                        ------------------
         SECTION 2.03.  Intentionally Omitted............................................. -17-
                        ---------------------
         SECTION 2.04   Disbursement of Funds............................................. -17-
                        ---------------------
         SECTION 2.05   Notes............................................................. -18-
                        -----
         SECTION 2.06   Interest.......................................................... -18-
                        --------
         SECTION 2.07   Interest Periods.................................................. -19-
                        ----------------
         SECTION 2.08   Repayment of Loans................................................ -19-
                        ------------------
         SECTION 2.09   Termination or Reduction of Commitments........................... -20-
                        ---------------------------------------
         SECTION 2.10   Prepayments....................................................... -20-
                        -----------
         SECTION 2.11   Continuation and Conversion Options............................... -20-
                        -----------------------------------
         SECTION 2.12.  Fees.............................................................. -21-
                        ----
         SECTION 2.13   Payments, etc..................................................... -21-
                        -------------
         SECTION 2.14   Interest Rate Not Ascertainable, etc.............................. -22-
                        ------------------------------------
         SECTION 2.15   Illegality........................................................ -22-
                        ----------
         SECTION 2.16   Increased Costs................................................... -23-
                        ---------------
         SECTION 2.17   Change of Lending Office.......................................... -24-
                        ------------------------
         SECTION 2.18   Funding Losses.................................................... -24-
                        --------------
         SECTION 2.19   Sharing of Payments, etc.......................................... -24-
                        ------------------------
         SECTION 2.20   Taxes............................................................. -25-
                        -----
         SECTION 2.21   Pro Rata Treatment................................................ -27-
                        ------------------
         SECTION 2.22   Replacement Lenders............................................... -27-
                        -------------------

ARTICLE III
         Representations and Warranties................................................... -27-
         ------------------------------
         SECTION 3.01.  Organization; Powers.............................................. -27-
                        --------------------
         SECTION 3.02.  Authorization; Enforceability..................................... -28-
                        -----------------------------
         SECTION 3.03.  Governmental Approvals; No Conflicts.............................. -28-
                        ------------------------------------
         SECTION 3.04.  Financial Condition; No Material Adverse Effect................... -28-
                        -----------------------------------------------
         SECTION 3.05.  Properties........................................................ -28-
                        ----------
         SECTION 3.07.  Compliance with Laws and Agreements............................... -29-
                        -----------------------------------
         SECTION 3.08.  Investment and Holding Company Act Status......................... -29-
                        -----------------------------------------
         SECTION 3.09.  Taxes............................................................. -29-
                        -----
         SECTION 3.10.  ERISA............................................................. -29-
                        -----
         SECTION 3.11.  Disclosure........................................................ -29-
                        ----------
         SECTION 3.12.  Subsidiaries...................................................... -29-
                        ------------
         SECTION 3.13.  Margin Securities................................................. -30-
                        -----------------
</TABLE>

                                      -i-
<PAGE>

<TABLE>
<S>                                                                                        <C>
ARTICLE IV
         Conditions....................................................................... -30-
         ----------
         SECTION 4.01.  Effective Date.................................................... -30-
                        --------------
         SECTION 4.02.  Each Credit Event................................................. -31-
                        -----------------
         SECTION 4.03.  Conversion........................................................ -31-
                        ----------

ARTICLE V
         Affirmative Covenants............................................................ -32-
         ---------------------
         SECTION 5.01.  Financial Statements and Other Information........................ -32-
                        ------------------------------------------
         SECTION 5.02.  Notices of Material Events........................................ -33-
                        --------------------------
         SECTION 5.03.  Existence; Conduct of Business.................................... -33-
                        ------------------------------
         SECTION 5.04.  Payment of Obligations............................................ -33-
                        ----------------------
         SECTION 5.05.  Maintenance of Properties; Insurance.............................. -33-
                        ------------------------------------
         SECTION 5.06.  Books and Records; Inspection Rights.............................. -34-
                        ------------------------------------
         SECTION 5.07.  Compliance with Laws, Material Contractual Obligations............ -34-
                        ------------------------------------------------------
         SECTION 5.08.  Use of Proceeds................................................... -34-
                        ---------------
         SECTION 5.09.  Additional Subsidiaries........................................... -34-
                        -----------------------
         SECTION 5.10.  Environmental Matters............................................. -34-
                        ---------------------

ARTICLE VI
         Negative Covenants............................................................... -34-
         ------------------
         SECTION 6.01.  Indebtedness...................................................... -34-
                        ------------
         SECTION 6.02.  Liens............................................................. -35-
                        -----
         SECTION 6.03.  Fundamental Changes............................................... -36-
                        -------------------
         SECTION 6.04.  Guarantees........................................................ -36-
                        ----------
         SECTION 6.05.  Hedging Agreements................................................ -36-
                        ------------------
         SECTION 6.06.  Restricted Payments............................................... -37-
                        -------------------
         SECTION 6.07.  Transactions with Affiliates...................................... -37-
                        ----------------------------
         SECTION 6.08.  Restrictive Agreements............................................ -37-
                        ----------------------
         SECTION 6.09.  Change in Fiscal Year............................................. -38-
                        ---------------------
         SECTION 6.10.  Asset Sales....................................................... -38-
                        -----------
         SECTION 6.11.  Sale and Leaseback Transactions................................... -38-
                        -------------------------------
         Section 6.12.  "Margin Calls" on Hedging Agreements.............................. -38-
                         -----------------------------------
         SECTION 6.13.  Designation of Restricted Subsidiaries............................ -39-
                        --------------------------------------

ARTICLE VII
         Financial Covenants.............................................................. -39-
         -------------------
         SECTION 7.01.  Adjusted Consolidated Net Worth................................... -39-
                        -------------------------------
         SECTION 7.02.  Debt Coverage Ratios.............................................. -39-
                        --------------------

ARTICLE VIII
         Events of Default................................................................ -39-
         -----------------

ARTICLE IX
         The Administrative Agent......................................................... -41-
         ------------------------
</TABLE>

                                     -ii-
<PAGE>

<TABLE>
<S>                                                                                        <C>
ARTICLE X
         Miscellaneous.................................................................... -43-
         -------------
         SECTION 10.01.  Notices.......................................................... -43-
                         -------
         SECTION 10.02.  Waivers; Amendments.............................................. -43-
                         -------------------
         SECTION 10.03.  Expenses; Indemnity; Damage Waiver............................... -44-
                         ----------------------------------
         SECTION 10.04.  Successors and Assigns........................................... -45-
                         ----------------------
         SECTION 10.05.  Survival......................................................... -47-
                         --------
         SECTION 10.06.  Counterparts; Integration; Effectiveness......................... -47-
                         ----------------------------------------
         SECTION 10.07.  Severability..................................................... -47-
                         ------------
         SECTION 10.08.  Right of Setoff.................................................. -47-
                         ---------------
         SECTION 10.09.  Governing Law; Jurisdiction; Consent to Service of Process....... -48-
                         ----------------------------------------------------------
         SECTION 10.10.  Waiver of Jury Trial............................................. -48-
                         --------------------
         SECTION 10.11.  Headings......................................................... -48-
                         --------
         SECTION 10.12.  Confidentiality.................................................. -49-
                         ---------------
         SECTION 10.13.  Interest Rate Limitation......................................... -49-
                         ------------------------
         SECTION 10.14   Unocal........................................................... -49-
                         ------
         SECTION 10.15   No Oral Agreements............................................... -49-
                         ------------------
</TABLE>

SCHEDULES:

Schedule 2.01 -- Commitments
Schedule 3.06 -- Disclosed Matters
Schedule 3.12 -- Subsidiaries
Schedule 6.01 -- Existing Indebtedness
Schedule 6.02 -- Existing Liens
Schedule 6.08 -- Existing Restrictions


EXHIBITS:
--------

Exhibit A -- Form of Assignment and Acceptance
Exhibit B -- Form of Note
Exhibit C -- Form of Opinion of Borrower's Counsel
Exhibit D  - Subsidiary Guaranty Agreement

                                     -iii-
<PAGE>

     CREDIT AGREEMENT dated as of September 29, 2000, among PURE RESOURCES,
INC., the LENDERS party hereto, THE CHASE MANHATTAN BANK, as Administrative
Agent, FIRST UNION NATIONAL BANK, as Syndication Agent, and CREDIT LYONNAIS NEW
YORK BRANCH, as Documentation Agent.

          The parties hereto agree as follows:

                                   ARTICLE I

                                  Definitions
                                  -----------

          SECTION 1.01.  Defined Terms.  As used in this Agreement, the
                         -------------
following terms have the meanings specified below:

          "ABR", when used in reference to any Loan or Borrowing, refers to
           ---
whether such Loan, or the Loans comprising such Borrowing, are bearing interest
at a rate determined by reference to the Alternate Base Rate.

          "Adjusted LIBO Rate" means, with respect to any Eurodollar Borrowing
           ------------------
for any Interest Period, an interest rate per annum (rounded upwards, if
necessary, to the nearest 1/100th of 1%) equal to (a) the LIBO Rate for such
Interest Period multiplied by (b) the Statutory Reserve Rate.

          "Administrative Agent" means The Chase Manhattan Bank, in its capacity
           --------------------
as administrative agent for the Lenders hereunder.

          "Administrative Questionnaire" means an Administrative Questionnaire
           ----------------------------
in a form supplied by the Administrative Agent.

          "Advance Notice" means written or facsimile notice (or telephonic
           --------------
notice promptly confirmed in writing), which in each case shall be irrevocable,
from the Borrower to be received by the Administrative Agent before 10:00 a.m.
(Houston time), by the number of Business Days in advance of any borrowing,
conversion, continuation or prepayment of any Loan pursuant to this Agreement as
respectively indicated below:

          (i)  Eurodollar Loans - 3 Business Days; and

          (ii) ABR Loans - same Business Day.

          For the purpose of determining the respectively applicable Loan in the
case of the conversion from one type of Loan into another, the Loan into which
there is to be a conversion shall control.  The Administrative Agent and each
Lender are entitled to rely upon and act upon facsimile notice made or
purportedly made by the Borrower, and the Borrower hereby waives the right to
dispute the authenticity and validity of any such facsimile once the
Administrative Agent or any Lender has advanced funds, absent manifest error.

          "Affiliate" means, with respect to a specified Person, another Person
           ---------
that directly, or indirectly through one or more intermediaries, Controls or is
Controlled by or is under common Control with the Person specified.
<PAGE>

          "Alternate Base Rate" means, for any day, a rate per annum equal to
           -------------------
the greatest of (a) the Prime Rate in effect on such day, and (b) the Federal
Funds Effective Rate in effect on such day plus 1/2 of 1%.  Any change in the
Alternate Base Rate due to a change in the Prime Rate or the Federal Funds
Effective Rate shall be effective from and including the effective date of such
change in the Prime Rate or the Federal Funds Effective Rate, respectively.

          "Applicable Percentage" means, with respect to any Lender, the
           ---------------------
percentage of the total Commitments represented by such Lender's Commitment.  If
the Commitments have terminated or expired, the Applicable Percentages shall be
determined based upon the Commitments most recently in effect, giving effect to
any assignments.

          "Applicable Rate" means, for any day, with respect to any ABR Loan or
           ---------------
Eurodollar Loan, or with respect to the facility fees payable hereunder, as the
case may be, the applicable rate per annum set forth below under the caption
"ABR Spread", "Eurodollar Spread" or "Facility Fee Rate", as the case may be:

<TABLE>
<CAPTION>
     ====================================================================
                                        ABR    Eurodollar   Facility Fee
                                      -------  -----------  -------------
        Debt Coverage Ratio:          Spread     Spread         Rate
        -------------------           -------  -----------  -------------
     <S>                              <C>      <C>          <C>
           "Category 1"
            ----------
       Less than 2.0 to 1.0            0.00%        0.85%          0.15%

     ---------------------------------------------------------------------
           "Category 2"
            ----------
     Equal to or greater than 2.0
      to 1.0 but less than 3.0 to
                1.0                    0.00%       0.925%          0.20%
     ---------------------------------------------------------------------
           "Category 3"
            ----------
        Equal to or Greater
          than 3.0 to 1.0              0.00%        1.00%          0.25%

     =====================================================================
</TABLE>

          For purposes of the foregoing (i) the Debt Coverage Ratio shall be
determined as of the end of each fiscal quarter of the Borrower's fiscal year
based upon the Borrower's consolidated financial statements delivered pursuant
to Section 5.01(a) or (b); provided, however, for the period from and after the
                           --------  -------
Effective Date to the date the first financial statements are delivered pursuant
to Section 5.01(b), Category 1 shall apply, and (ii) each change in the
Applicable Rate resulting from a change in the Debt Coverage Ratio shall be
effective during the period commencing on and including the date of delivery to
the Administrative Agent of such consolidated financial statements indicating
such change and ending on the date immediately preceding the effective date of
the next such change; provided further  that the Debt Coverage Ratio shall be
                      -------- -------
deemed to be in Category 3 at the option of the Administrative Agent or at the
request of the Required Lenders (A) at any time that an Event of Default has
occurred and is continuing or (B)  if the Borrower fails to deliver the
consolidated financial statements required to be delivered by it pursuant to
Section 5.01(a) or (b), during the period from the expiration of the time for
delivery thereof until such consolidated financial statements are delivered.

          Notwithstanding the foregoing, if (a) UNOCAL does not own more than a
51% Equity Interest in the Borrower, or (b) insiders or nominees of UNOCAL do
not constitute a majority of the board of directors of the Borrower, then the
Eurodollar Spread for each Category shall be increased by 0.125%.

                                      -2-
<PAGE>

          "Assignment and Acceptance" means an assignment and acceptance entered
           -------------------------
into by a Lender and an assignee (with the consent of any party whose consent is
required by Section 10.04), and accepted by the Administrative Agent, in the
form of Exhibit A or any other form approved by the Administrative Agent and the
Borrower.

          "Availability Period" means the period from and including the
           -------------------
Effective Date to but excluding the earlier of the Conversion Date and the date
of termination of the Commitments.

          "Board" means the Board of Governors of the Federal Reserve System of
           -----
the United States of America.

          "Borrower" means Pure Resources, Inc., a Delaware corporation.
           --------

          "Borrowing" means Loans of the same Type, made, converted or continued
           ---------
on the same date and, in the case of Eurodollar Loans, as to which a single
Interest Period is in effect.

          "Borrowing Request" means a request by the Borrower for a Borrowing in
           -----------------
accordance with Section 2.02.

          "Business Day" means any day that is not a Saturday, Sunday or other
           ------------
day on which commercial banks in New York City are authorized or required by law
to remain closed; provided that, when used in connection with a Eurodollar Loan,
                  --------
the term "Business Day" shall also exclude any day on which banks are not open
          ------------
for dealings in dollar deposits in the London interbank market.

          "Capital Lease Obligations" of any Person means the obligations of
           -------------------------
such Person to pay rent or other amounts under any lease of (or other
arrangement conveying the right to use) real or personal property, or a
combination thereof, which obligations are required to be classified and
accounted for as capital leases on a balance sheet of such Person under GAAP,
and the amount of such obligations shall be the capitalized amount thereof
determined in accordance with GAAP.

          "Change in Control" means (a) the acquisition of ownership, directly
           -----------------
or indirectly, beneficially or of record, by any Person or group (within the
meaning of the Securities Exchange Act of 1934 and the rules of the Securities
and Exchange Commission thereunder as in effect on the date hereof) other than
UNOCAL, of shares representing more than 35% of the aggregate ordinary voting
power represented by the issued and outstanding capital stock of the Borrower;
(b) occupation of a majority of the seats (other than vacant seats) on the board
of directors of the Borrower by Persons who were neither (i) nominated by the
board of directors of the Borrower nor (ii) appointed by directors so nominated;
or (c) the acquisition of direct or indirect Control of the Borrower by any
Person or group other than UNOCAL.

          "Code" means the Internal Revenue Code of 1986, as amended from time
           ----
to time.

          "Commitment" means, with respect to each Lender, the commitment of
           ----------
such Lender to make Loans hereunder,  expressed as an amount representing the
maximum aggregate amount of such Lender's Exposure hereunder, as such commitment
may be (a) reduced from time to time pursuant to Section 2.09 and (b) reduced or
increased from time to time pursuant to assignments by or to such Lender
pursuant to Section 10.04.  The initial amount of each Lender's Commitment is
set forth on Schedule 2.01, or in the Assignment and Acceptance pursuant to
which such Lender shall have assumed its Commitment, as applicable.  Subject to
Section 2.01(c)(ii), the initial aggregate amount of the Lenders' Commitments
is $210,000,000.00.

                                      -3-
<PAGE>

          "Consolidated Net Tangible Assets" means the total amount of assets
           --------------------------------
(excluding cash and cash equivalents) of the Borrower and its Restricted
Subsidiaries on a consolidated basis (less applicable reserves and other
properly deductible items) after deducting therefrom (a) all current liabilities
(excluding any which are, by their terms, extendable or renewable at the option
of the obligor thereon to a time more than 12 months after the time as of which
the amount thereof is being computed) and  (b) all goodwill, trade names,
trademarks, patents, unamortized debt premium or discount and expense and other
like intangible assets, determined in accordance with GAAP.

          "Control" means the possession, directly or indirectly, of the power
           -------
to direct or cause the direction of the management or policies of a Person,
whether through the ability to exercise voting power, by contract or otherwise.
"Controlling" and "Controlled" have meanings correlative thereto.
 -----------       ----------

          "Conversion" means the conversion of the outstanding Revolving Loans
           ----------
to Term Loans pursuant to the terms and conditions of Sections 2.01(e) and 4.03.

          "Conversion Date" means September 28, 2001.
           ---------------

          "Debt Coverage Ratio" means the ratio calculated in accordance with
           -------------------
Section 7.02.

          "Default" means any event or condition which constitutes an Event of
           -------
Default or which upon notice, lapse of time or both would, unless cured or
waived, become an Event of Default.

          "Disclosed Matters" means the actions, suits and proceedings and the
           -----------------
environmental matters disclosed in Schedule 3.06.

          "dollars" or "$" refers to lawful money of the United States of
           -------      -
America.

          "EBITDAX" shall mean, for any period, the sum of consolidated net
           -------
income for such period plus the following expenses or charges to the extent
deducted from consolidated net income in such period: interest expense, taxes,
depreciation, depletion, amortization and exploration expenses.  As used herein,
"consolidated net income" shall mean, for any period, the amount which, in
 -----------------------
conformity with GAAP, would be set forth opposite the caption "net income or
loss" (or any like caption) on a consolidated income statement of the Borrower
and its Restricted Subsidiaries (before deducting minority interests in net
income of Restricted Subsidiaries, but disregarding (a) all noncash
extraordinary or unusual items, (b) write-downs after June 30, 2000 under FASB
Statement No. 19, (c) non-cash write-ups or write-downs of assets after June
30, 2000 under FASB Statement No. 121, (d) non-cash gains, losses or
adjustments under FASB Statement No. 133, in calculating such consolidated net
income), and (e) the effects of common stock of the Borrower being repurchased
or being subject to repurchase under Employment Arrangements accounted for as
variable plans under APB Opinion No. 25 (provided that any new arrangements
entered into after the Effective Date as well as any amendments to arrangements
existing on the Effective Date, shall not be excluded to the extent that such
arrangements materially increase the Borrower's obligations); provided however,
                                                              -------- -------
that in determining consolidated net income for any period of four fiscal
quarters that includes the acquisition by the Borrower or any of its
consolidated Restricted Subsidiaries of Restricted Subsidiaries (whether by
purchase, merger or otherwise) or of producing Oil and Gas Properties, such
acquired Restricted Subsidiaries shall be included in such calculation on a pro
forma basis as if they had been owned by the Borrower and its consolidated
Restricted Subsidiaries throughout such four fiscal quarter period and the
revenues attributable to the oil and gas production from such acquired
properties during such four fiscal quarter period, less the direct operating
expenses and severance and ad valorem taxes incurred with respect to such
properties during such four fiscal quarter period, shall be included in such
calculation as part of such

                                      -4-
<PAGE>

consolidated net income and the revenues attributable to the oil and gas
production from any producing Oil and Gas Properties sold during such four
fiscal quarter period, less the direct operating expenses and severance and ad
valorem taxes incurred with respect to such properties during such four fiscal
quarter period, shall be pro forma deducted from such determination of
consolidated net income.

          "Effective Date" means the date on which the conditions specified in
           --------------
Section 4.01 are satisfied (or waived in accordance with Section 10.02).

          "Eligible Transferee" means any financial institution which is a
           -------------------
Lender as of the Effective Date or which is a commercial bank, a financial
institution or an "accredited investor" (as defined in Regulation D) which makes
loans in the ordinary course of its business and that makes or acquires Loans
for its own account in the ordinary course of its business and which has
capital, surplus and undivided profits aggregating at least $250,000,000 (as of
the date of its most recent financial statements).

          "Employment Arrangements" means severance arrangements, employment
           -----------------------
agreements, retention bonus agreements or similar arrangements, whether now
existing or hereafter entered into, with officers and employees of the Borrower
or its Subsidiaries.

          "Environmental Laws" means all laws, rules, regulations, codes,
           ------------------
ordinances, orders, decrees, judgments, injunctions, notices or binding
agreements issued, promulgated or entered into by any Governmental Authority,
relating in any way to the environment, preservation or reclamation of natural
resources, the management, release or threatened release of any Hazardous
Material.

          "Environmental Liability" means any liability, contingent or otherwise
           -----------------------
(including any liability for damages, costs of environmental remediation, fines,
penalties or indemnities), of the Borrower or any Subsidiary directly or
indirectly resulting from or based upon (a) violation of any Environmental Law,
(b) the generation, use, handling, transportation, storage, treatment or
disposal of any Hazardous Materials, (c) exposure to any Hazardous Materials,
(d) the release or threatened release of any Hazardous Materials into the
environment or (e) any contract, agreement or other consensual arrangement
pursuant to which liability is assumed or imposed with respect to any of the
foregoing.

          "Equity Interests" means shares of the capital stock, partnership
           ----------------
interests, membership interest in a limited liability company, beneficial
interests in a trust or other equity interests in the Borrower or any Subsidiary
or any warrants, options or other rights to acquire such interests.

          "ERISA" means the Employee Retirement Income Security Act of 1974, as
           -----
amended from time to time.

          "ERISA Affiliate" means any trade or business (whether or not
           ---------------
incorporated) that, together with the Borrower, is treated as a single employer
under Section 414(b) or (c) of the Code or, solely for purposes of Section 302
of ERISA and Section 412 of the Code, is treated as a single employer under
Section 414 of the Code; provided however, that in no event will UNOCAL or any
                         -------- -------
of its subsidiaries (other than Borrower and its Subsidiaries) be considered an
ERISA Affiliate.

          "ERISA Event" means (a) any "reportable event", as defined in Section
           -----------
4043 of ERISA or the regulations issued thereunder with respect to a Plan (other
than an event for which the 30-day notice period is waived); (b) the existence
with respect to any Plan of an "accumulated funding deficiency" (as defined in
Section 412 of the Code or Section 302 of ERISA), whether or not waived; (c) the
filing pursuant to Section 412(d) of the Code or Section 303(d) of ERISA of an
application for a waiver of the minimum

                                      -5-
<PAGE>

funding standard with respect to any Plan; (d) the incurrence by the Borrower or
any of its ERISA Affiliates of any liability under Title IV of ERISA with
respect to the termination of any Plan; (e) the receipt by the Borrower or any
ERISA Affiliate from the PBGC or a plan administrator of any notice relating to
an intention to terminate any Plan or Plans or to appoint a trustee to
administer any Plan; (f) the incurrence by the Borrower or any of its ERISA
Affiliates of any liability with respect to the withdrawal or partial withdrawal
from any Plan or Multiemployer Plan; or (g) the receipt by the Borrower or any
ERISA Affiliate of any notice, or the receipt by any Multiemployer Plan from the
Borrower or any ERISA Affiliate of any notice, concerning the imposition of
Withdrawal Liability or a determination that a Multiemployer Plan is, or is
expected to be, insolvent or in reorganization, within the meaning of Title IV
of ERISA.

          "Eurodollar", when used in reference to any Loan or Borrowing, refers
           ----------
to whether such Loan, or the Loans comprising such Borrowing, are bearing
interest at a rate determined by reference to the Adjusted LIBO Rate.

          "Event of Default" has the meaning assigned to such term in Article
           ----------------
VIII.

          "Existing Titan Credit Facility" means the $250,000,000 revolving
           ------------------------------
credit facility under that certain Amended and Restated Credit Agreement dated
as of June 24, 1999, among Titan Exploration, Inc., as Borrower, Chase Bank of
Texas, National Association, as Administrative Agent, First Union National Bank,
as Documentation Agent, Morgan Guaranty Trust Company of New York, as
Syndication Agent, and the lenders party thereto, together with any and all
amendments and supplements thereto.

          "Exposure" means, with respect to any Lender at any time, the sum of
           --------
the outstanding principal amount of such Lender's Loans at such time.

          "FASB" means the Financial Accounting Standards Board.
           ----

          "Federal Funds Effective Rate" means, for any day, the weighted
           ----------------------------
average (rounded upwards, if necessary, to the next 1/100 of 1%) of the rates on
overnight Federal funds transactions with members of the Federal Reserve System
arranged by Federal funds brokers, as published on the next succeeding Business
Day by the Federal Reserve Bank of New York, or, if such rate is not so
published for any day that is a Business Day, the average (rounded upwards, if
necessary, to the next 1/100 of 1%) of the quotations for such day for such
transactions received by the Administrative Agent from three Federal funds
brokers of recognized standing selected by it.

          "Final Maturity Date" means September 29, 2002.
           -------------------

          "Financial Officer" means the chief financial officer, principal
           -----------------
accounting officer, treasurer or controller of the Borrower.

          "5-Year Credit Agreement" means that certain Credit Agreement dated as
           -----------------------
of September 29, 2000, among the Borrower, The Chase Manhattan Bank, as
Administrative Agent, First Union National Bank, as Syndication Agent, and the
lenders party thereto, together with any and all amendments and supplements
thereto.

          "5-Year Revolving Credit Facility" means the $250,000,000 revolving
           --------------------------------
credit facility under the 5-Year Credit Agreement.

                                      -6-
<PAGE>

          "Funded Indebtedness" means, at any time and without duplication, all
           --------------------
obligations of the Borrower and its Restricted Subsidiaries on a consolidated
basis for (a) borrowed money and any other obligations evidenced by bonds,
debentures, notes, or other similar instruments, (b) all obligations outstanding
for 180 days or more to deliver goods or services including Hydrocarbons in
consideration of advanced payments, (c) the undischarged balance of any
production payment created by such Person or for the creation of which such
Person directly received payment, (d) all Capital Lease Obligations, (e) all
letters of credit issued in connection with Hedging Agreements, (f) all
unreimbursed "LC Disbursements" (as defined in the 5-Year Credit Agreement), (g)
all Put Arrangement Liabilities, and (h) all Guarantees by the Borrower and its
Restricted Subsidiaries on a consolidated basis of the type of obligations
described in clauses (a) through (f) of this definition.

          "GAAP" means generally accepted accounting principles in the United
           ----
States of America.

          "Governmental Authority" means the government of the United States of
           ----------------------
America, any other nation or any political subdivision thereof, whether state or
local, and any agency, authority, instrumentality, regulatory body, court,
central bank or other entity exercising executive, legislative, judicial,
taxing, regulatory or administrative powers or functions of or pertaining to
government.

          "Guarantee" of or by any Person (the "guarantor") means any
           ---------                            ---------
obligation, contingent or otherwise, of the guarantor guaranteeing or having the
economic effect of guaranteeing any Indebtedness of any other Person (the
"primary obligor") in any manner, whether directly or indirectly, and including
----------------
any obligation of the guarantor, direct or indirect, (a) to purchase or pay (or
advance or supply funds for the purchase or payment of) such Indebtedness or to
purchase (or to advance or supply funds for the purchase of) any security for
the payment thereof, (b) to purchase or lease property, securities or services
for the purpose of assuring the owner of such Indebtedness of the payment
thereof, (c) to maintain working capital, equity capital or any other financial
statement condition or liquidity of the primary obligor so as to enable the
primary obligor to pay such Indebtedness or (d) as an account party in respect
of any letter of credit or letter of guaranty issued to support such
Indebtedness; provided, that the term Guarantee shall not include endorsements
              --------
for collection or deposit in the ordinary course of business.

          "Hazardous Materials"  means all explosive or radioactive substances
           -------------------
or wastes and all hazardous or toxic substances, wastes or other pollutants,
asbestos or asbestos containing materials, polychlorinated biphenyls, radon gas,
infectious or medical wastes and all other substances or wastes of any nature
regulated pursuant to any Environmental Law and petroleum, petroleum products or
distillates and associated oil or natural gas exploration, production and
development wastes only to the extent that they are not exempted or excluded
from being included as "hazardous substances," "hazardous materials," "hazardous
wastes" and toxic substances under such Environmental Laws.

          "Hedging Agreement" means any interest rate protection agreement,
           -----------------
foreign currency exchange agreement, commodity price protection agreement or
other interest or currency exchange rate or commodity price hedging arrangement.

          "Hydrocarbon Interests" means all rights, titles, interests and
           ---------------------
estates now or hereafter acquired in and to oil and gas leases, oil, gas and
mineral leases, or other liquid or gaseous hydrocarbon leases, mineral fee
interests, overriding royalty and royalty interests, net profit interests and
production payment interests, including any reserved or residual interests of
whatever nature.

                                      -7-
<PAGE>

          "Hydrocarbons" means oil, gas, casinghead gas, drip gasoline, natural
           ------------
gasoline, condensate, distillate, liquid hydrocarbons, gaseous hydrocarbons and
all products refined or separated therefrom.

          "Indebtedness" of any Person means, without duplication, (a) all
           ------------
obligations of such Person for borrowed money (including principal, interest,
fees and charges), (b) all obligations of such Person evidenced by bonds,
debentures, notes or similar instruments (including principal, interest, fees
and charges), (c) the undischarged balance of any production payment created by
such Person or for the creation of which such Person directly received payment,
(d) all obligations of such Person issued or assumed as the deferred purchase
price of Property or services (excluding trade accounts payable and accrued
obligations incurred in the ordinary course of business so long as the same are
not 180 days overdue or, if overdue, are being contested in good faith and by
appropriate proceedings), (e) all Indebtedness of others secured by (or for
which the holder of such Indebtedness has an existing right, contingent or
otherwise, to be secured by) any Lien on Property owned or acquired by such
Person, whether or not the obligations secured thereby have been assumed, (f)
all Guarantees of Indebtedness of others, (g) all Capital Lease Obligations of
such Person, (h) all recourse obligations of such Person with respect to sales
of accounts receivable which would be shown under GAAP on the balance sheet of
such Person as a liability, (i) all obligations, contingent or otherwise, of
such Person as an account party (including reimbursement obligations to the
issuer of a letter of credit) in respect of bankers' acceptances and letters of
credit guaranteeing Indebtedness, (j) all noncontingent obligations of such
Person as an account party (including reimbursement obligations to the issuer of
a letter of credit) in respect of letters of credit other than those referred to
in clause (i) above, (k) all obligations under leases which require such Person
to make payments over the term of such lease, including payments at termination,
which are substantially equal to at least eighty percent (80%) of the purchase
price of the Property subject to such lease plus interest at an imputed rate of
interest, (l) all obligations or undertakings of such Person to maintain or
cause to be maintained the financial position or covenants of others or to
purchase the Indebtedness or Property of others, (m) obligations outstanding for
180 days or more to deliver goods or services including Hydrocarbons in
consideration of advance payments, (n) any stock of such Person in which such
Person has a mandatory obligation to redeem such stock within two (2) years
after the Final Maturity Date (plus any extension of such date), but excluding
mandatory redemptions in connection with Employment Arrangements, (o) all
Indebtedness of any Person shall include the Indebtedness of any other entity
(including any partnership in which such Person is a general partner) to the
extent such Person is liable therefor as a result of such Person's ownership
interest in or other relationship with such entity, except to the extent the
terms of such Indebtedness provide that such Person is not liable therefor, (p)
the undischarged balance of any production payment created by such Person or for
the creation of which such Person directly received payment; and (q) all
obligations of such Person under Hedging Agreements.  The Indebtedness of any
Person shall exclude obligations under leases which are characterized as
operating leases.

          "Interest Payment Date" means (a) with respect to any ABR Loan, the
           ---------------------
last day of each March, June, September and December, (b) with respect to any
Eurodollar Loan, the last day of the Interest Period applicable to the Borrowing
of which such Loan is a part and, in the case of a Eurodollar Borrowing with an
Interest Period of more than three months' duration, each day prior to the last
day of such Interest Period that occurs at intervals of three months' duration
after the first day of such Interest Period.

          "Interest Period" means  with respect to any Eurodollar Borrowing, the
           ---------------
period commencing on the date of such Borrowing and ending on the numerically
corresponding day in the calendar month that is one, two, three, six or (with
the consent of each Lender) nine or twelve months thereafter, as the Borrower
may elect; provided, that (i) if any Interest Period would end on a day other
           --------
than a Business Day, such Interest Period shall be extended to the next
succeeding Business Day unless such next succeeding Business

                                      -8-
<PAGE>

Day would fall in the next calendar month, in which case such Interest Period
shall end on the next preceding Business Day and (ii) any Interest Period that
commences on the last Business Day of a calendar month (or on a day for which
there is no numerically corresponding day in the last calendar month of such
Interest Period) shall end on the last Business Day of the last calendar month
of such Interest Period. For purposes hereof, the date of a Borrowing initially
shall be the date on which such Borrowing is made and thereafter shall be the
effective date of the most recent conversion or continuation of such Borrowing.

          "Lender Affiliate" means, (a) with respect to any Lender, (i) an
           ----------------
Affiliate of such Lender or (ii) any entity (whether a corporation, partnership,
trust or otherwise) that is engaged in making, purchasing, holding or otherwise
investing in bank loans and similar extensions of credit in the ordinary course
of its business and is administered or managed by a Lender or an Affiliate of
such Lender and (b) with respect to any Lender that is a fund which invests in
bank loans and similar extensions of credit, any other fund that invests in bank
loans and similar extensions of credit and is managed by the same investment
advisor as such Lender or by an Affiliate of such investment advisor.

          "Lenders" means the Persons listed on Schedule 2.01 and any other
           -------
Person that shall have become a party hereto pursuant to an Assignment and
Acceptance, other than any such Person that ceases to be a party hereto pursuant
to an Assignment and Acceptance.

          "Lending Office" means for each Lender the office specified under such
           --------------
Lender's name on its signature page hereto, or in the Assignment and Acceptance
pursuant to which it became a Lender, with respect to each Type of Loan, or such
other office as such Lender may designate in writing from time to time to the
Borrower and the Administrative Agent with respect to such Type of Loan.

          "LIBO Rate" means, with respect to any Eurodollar Borrowing for any
           ---------
Interest Period, the rate appearing on Page 3750 of the Telerate Service (or on
any successor or substitute page of such Service, or any successor to or
substitute for such Service, providing rate quotations comparable to those
currently provided on such page of such Service, as determined by the
Administrative Agent from time to time for purposes of providing quotations of
interest rates applicable to dollar deposits in the London interbank market) at
approximately 11:00 a.m., London time, two Business Days prior to the
commencement of such Interest Period, as the rate for dollar deposits with a
maturity comparable to such Interest Period.  If for any reason such rate is not
available, the term "LIBO Rate" means, for any Eurodollar Borrowing for any
Interest Period therefor, the rate per annum (rounded upwards, if necessary, to
the nearest 1/100 of 1%) appearing on Reuters Screen LIBO Page as the London
interbank offered rate for deposits in Dollars at approximately 11:00 a.m.
(London time) two Business Days prior to the first day of such Interest Period
for a term comparable to such Interest Period; provided, however, if more than
                                               --------  -------
one rate is specified on Reuters Screen LIBO Page, the applicable rate shall be
the arithmetic mean of all such rates.

          "Lien" means, with respect to any asset, (a) any mortgage, deed of
           ----
trust, lien, pledge, hypothecation, encumbrance, charge or security interest in,
on or of such asset, and (b) the interest of a vendor or a lessor under any
conditional sale agreement, capital lease or title retention agreement (or any
financing lease having substantially the same economic effect as any of the
foregoing) relating to such asset.

          "Loan Documents" means this Agreement, the Subsidiary Guaranty
           --------------
Agreements and any and all other agreements or instruments now or hereafter
executed and delivered by the Borrower or any other Person (other than Hedging
Agreements or participation or similar agreements between any Lender and any
other lender or creditor with respect to any Indebtedness pursuant to this
Agreement) in connection with, or as security for the payment or performance of
this Agreement, as such agreements may be amended, supplemented or restated from
time to time.

                                      -9-
<PAGE>

          "Loan Parties" means the Borrower and the Restricted Subsidiaries.
           ------------

          "Loans" means (a) during the Availability Period, the Revolving Loans,
           -----
and (b) from and after the Conversion Date, the Term Loans, as the case may be.

          "Material Adverse Effect" means a material adverse effect on (a) the
           -----------------------
assets, liabilities, financial condition or operations of the Borrower and the
Restricted Subsidiaries taken as a whole, as indicated in the most recent
quarterly or annual financial statements (excluding decreases in hydrocarbon
prices) delivered pursuant to Section 5.01 or (b) the ability of the Borrower
and the Restricted Subsidiaries to perform their respective monetary obligations
under this Agreement on a timely basis.

          "Material Indebtedness" means Funded Indebtedness (other than the
           ---------------------
Loans) of any one or more of the Borrower and its Restricted Subsidiaries in an
aggregate principal amount exceeding $25,000,000.

          "Material Subsidiary" means any Restricted Subsidiary of the Borrower
           -------------------
whose percentage of the Consolidated Net Tangible Assets represented by such
Restricted Subsidiary's portion of such Consolidated Net Tangible Assets (after
intercompany eliminations) exceeds 5% as of the end of the most recently
completed fiscal quarter.

          "Moody's" means Moody's Investors Service, Inc.
           -------

          "Multiemployer Plan" means a multiemployer plan as defined in Section
           ------------------
4001(a)(3) of ERISA.

          "Oil and Gas Properties" means Hydrocarbon Interests; the Properties
           ----------------------
now or hereafter pooled or unitized with Hydrocarbon Interests; all presently
existing or future unitization, pooling agreements and declarations of pooled
units and the units created thereby (including without limitation all units
created under orders, regulations and rules of any Governmental Authority) which
may affect all or any portion of the Hydrocarbon Interests; all operating
agreements, contracts and other agreements which relate to any of the
Hydrocarbon Interests or the production, sale, purchase, exchange or processing
of Hydrocarbons from or attributable to such Hydrocarbon Interests; all
Hydrocarbons in and under and which may be produced and saved or attributable to
the Hydrocarbon Interests, including all oil in tanks, the lands covered thereby
and all rents, issues, profits, proceeds, products, revenues and other incomes
from or attributable to the Hydrocarbon Interests; all tenements, hereditaments,
appurtenances and Properties in any manner appertaining, belonging, affixed or
incidental to the Hydrocarbon Interests; and all Properties, rights, titles,
interests and estates described or referred to above, including any and all
Property, real or personal, now owned or hereinafter acquired and situated upon,
used, held for use or useful in connection with the operating, working or
development of any of such Hydrocarbon Interests or Property (excluding drilling
rigs, automotive equipment or other personal property which may be on such
premises for the purpose of drilling a well or for other similar temporary uses)
and including any and all oil wells, gas wells, injection wells or other wells,
buildings, structures, fuel separators, liquid extraction plants, plant
compressors, pumps, pumping units, field gathering systems, tanks and tank
batteries, fixtures, valves, fittings, machinery and parts, engines, boilers,
meters, apparatus, equipment, appliances, tools, implements, cables, wires,
towers, casing, tubing and rods, surface leases, rights-of-way, easements and
servitudes together with all additions, substitutions, replacements, accessions
and attachments to any and all of the foregoing.

          "Other Taxes" has the meaning set forth in Section 2.20(b).
           -----------

                                     -10-
<PAGE>

          "Payment Office" means the Administrative Agent's office located at
           --------------
712 Main Street, Houston, Texas 77002.

          "PBGC" means the Pension Benefit Guaranty Corporation referred to and
           ----
defined in ERISA and any successor entity performing similar functions.

          "Percentage Share" means, as to any Lender, the fraction, expressed as
           ----------------
a percentage, the numerator of which is the amount of such Lender's Commitment
and the denominator of which is the amount of the total Commitments.

          "Permitted Encumbrances" means:
           ----------------------

          (a)  Liens imposed by law for taxes, assessments or other governmental
charges or levies that are not yet due or are being contested in compliance with
Section 5.04;

          (b)  carriers', warehousemen's, mechanics', materialmen's, repairmen's
and other like Liens imposed by law or created in the ordinary course of
business and securing obligations that are not overdue by more than 90 days or
are being contested in compliance with Section 5.04;

          (c)  Liens (other than any inchoate lien imposed by ERISA) incurred or
deposits or pledges made in the ordinary course of business in connection with
workers' compensation, unemployment insurance and other types of social
security, old age or other similar obligations, or to secure the performance of
tenders, statutory obligations, surety and appeal bonds, bids, leases,
government contracts, performance and return of money bonds and other similar
obligations;

          (d)  judgment Liens in respect of judgments that do not constitute an
Event of Default under clause (k) of Article VII;

          (e)  easements, rights-of-way, restrictions, servitudes, permits,
reservations, exceptions, conditions, covenants and other similar charges or
encumbrances not interfering with the ordinary conduct of the business of the
Borrower or any of its Restricted Subsidiaries;

          (f)  any Lien securing Indebtedness, neither assumed nor guaranteed by
the Borrower or any of its Restricted Subsidiaries nor on which it customarily
pays interest, existing upon real estate or rights in or relating to real estate
acquired by the Borrower or any Restricted Subsidiary for substation, metering
station, pump station, storage, gathering line, transmission line,
transportation line, distribution line or for right-of-way purposes, and any
Liens reserved in leases for rent and for compliance with the terms of the
leases in the case of leasehold estates, to the extent that any such Lien
referred to in this clause (f) does not materially impair the use of the
Property covered by such Lien for the purposes of which such Property is held by
the Borrower or any of its Restricted Subsidiaries;

          (g)  Liens reserved in oil, gas and/or mineral leases for bonus or
rental payments and for compliance with the terms of such leases and Liens
reserved in operating agreements, farm-out and farm-in agreements, exploration
agreements, development agreements and other similar agreements for compliance
with the terms of such agreements;

          (h)  defects, irregularities and deficiencies in title of any rights
of way or other property of the Borrower or any Restricted Subsidiary which in
the aggregate do not materially impair the use of such rights of way or other
property for the purposes for which such rights of way and other property are
held by

                                     -11-
<PAGE>

the Borrower or any Restricted Subsidiary, and defects, irregularities and
deficiencies in title to any property of the Borrower or its Restricted
Subsidiaries, which defects, irregularities or deficiencies have been cured by
possession under applicable statutes of limitation;

          (i) royalties, overriding royalties, revenue interests, net revenue
interests, production payments (other than production payments which constitute
Indebtedness), advance payment obligations (other than obligations in respect of
advance payment received by the Borrower or any Restricted Subsidiary in
connection with the borrowing of money) and other similar burdens (i) now
existing on Oil and Gas Properties now owned or (ii) as to Oil and Gas
Properties hereafter acquired, existing at the time of acquisition by the
Borrower or any of its Restricted Subsidiaries or (iii) entered into in the
ordinary course of business;

          (j) Liens arising out of all presently existing and future division
and transfer orders, advance payment agreements, processing contracts, gas
processing plant agreements, operating agreements, gas balancing or deferred
production agreements, pooling, unitization or communitization agreements,
pipeline, gathering or transportation agreements, platform agreements, drilling
contracts, injection or repressuring agreements, cycling agreements,
construction agreements, salt water or other disposal agreements, leases or
rental agreements (but only as otherwise not prohibited by this Agreement),
farm-out and farm-in agreements, exploration and development agreements, and any
and all other contracts or agreements covering, arising out of, used or useful
in connection with or pertaining to the exploration, development, operation,
production, sale, use, purchase, exchange, storage, separation, dehydration,
treatment, compression, gathering, transportation, processing, improvement,
marketing, disposal or handling of any property of the Borrower or its
Restricted Subsidiaries, provided such agreements are entered into in the
ordinary course of business and contain terms customary for such agreements in
the industry;

          (k) Liens arising from UCC financing statements regarding leases
permitted by this Agreement;

          (l) Liens incurred by the Borrower with the consent of the Required
Lenders; and

          (m) Liens securing the Existing Titan Credit Facility as to which the
Administrative Agent has been provided proper releases to be filed
contemporaneous with the execution of this Agreement.

          "Permitted Investments" means:
           ---------------------

          (a) direct obligations of, or obligations the principal of and
interest on which are unconditionally guaranteed by, the United States of
America (or by any agency thereof to the extent such obligations are backed by
the full faith and credit of the United States of America), in each case
maturing within one year from the date of acquisition thereof;

          (b) investments in commercial paper maturing within 270 days from the
date of acquisition thereof and having, at such date of acquisition, the highest
or second highest credit rating obtainable from S&P or from Moody's;

          (c) investments in certificates of deposit, banker's acceptances and
time deposits maturing within one year from the date of acquisition thereof
issued or guaranteed by or placed with, and money market deposit accounts issued
or offered by, any domestic office of any commercial bank organized under the
laws of the United States of America or any State thereof which has a combined
capital and surplus and undivided profits of not less than $500,000,000;

                                     -12-
<PAGE>

          (d) fully collateralized repurchase agreements with a term of not more
than 30 days for securities described in clause (a) above and entered into with
a financial institution satisfying the criteria described in clause (c) above.

          (e) investments in funds substantially all of the assets of which are
of the type described in clause (a), (b) or (c) above;

          (f) loans or advances by Borrower or any Restricted Subsidiary to or
investments in Borrower or a Person that is (or that simultaneously becomes) a
Restricted Subsidiary;

          (g) loans or advances to employees of the Borrower or its Subsidiaries
in the ordinary course of business not to exceed $2,000,000 in the aggregate at
any one time outstanding;

          (h) loans made to employees of the Borrower or its Subsidiaries for
the purposes of funding the exercise of outstanding options pursuant to the
Borrower's stock option plans not to exceed $55,000,000 in the aggregate at any
one time outstanding; and

          (i) Guarantees permitted under Section 6.04.

          "Person" means any natural person, corporation, limited liability
           ------
company, trust, joint venture, association, company, partnership, Governmental
Authority or other entity.

          "Plan"  means any employee pension benefit plan (other than a
           ----
Multiemployer Plan) subject to the provisions of Title IV of ERISA or Section
412 of the Code or Section 302 of ERISA, and in respect of which the Borrower or
any ERISA Affiliate is (or, if such plan were terminated, would under Section
4069 of ERISA be deemed to be) an "employer" as defined in Section 3(5) of
ERISA.

          "Prime Rate" means the rate of interest per annum publicly announced
           ----------
from time to time by The Chase Manhattan Bank as its prime rate in effect at its
principal office in New York City; each change in the Prime Rate shall be
effective from and including the date such change is publicly announced as being
effective.

          "Put Arrangement" means an agreement of Borrower or any Restricted
           ---------------
Subsidiary to repurchase or otherwise make a Restricted Payment in respect of
Equity Interests issued as consideration for an acquisition by Borrower or any
Restricted Subsidiary after the Effective Date (for example, to repurchase such
Equity Interests during a specified option period if a specified average closing
price of such Equity Interests is below a specified price target).

          "Put Arrangement Liability" means the amount which Borrower or any
           -------------------------
Restricted Subsidiary is obligated to pay in respect of Equity Interests under a
Put Arrangement (whether or not then exercised by the holder thereof) to the
extent such obligation is not contingent and at the time such obligation is not
contingent. For this purpose, an obligation under a Put Arrangement to
repurchase Equity Interests at the option of another Person is not contingent to
the extent and at the time that the option is presently exercisable; provided
                                                                     --------
however, such an option exercisable during a specified future option period will
-------
also be treated as not contingent during the 180-day period immediately
preceding the start of such option period to the extent a liability would have
existed under the Put Arrangement if such 180-day period had been part of such
option period.

          "Register" has the meaning set forth in Section 10.04.
           --------

                                     -13-
<PAGE>

          "Related Parties" means, with respect to any specified Person, such
           ---------------
Person's Affiliates and the respective directors, officers, employees, agents
and advisors of such Person and such Person's Affiliates.

          "Required Lenders" means, at any time, Lenders having Exposures and
           ----------------
unused Commitments representing at least 51% of the sum of the total Exposures
and unused Commitments at such time.

          "Restricted Investments" means (i) the cash amount or fair value (in
           ----------------------
the case of consideration other than cash) of any loans or advances to or
investments in any Person other than Permitted Investments or (ii) the net asset
value (being the fair value of its assets minus the fair value of its
liabilities) of a Restricted Subsidiary at the time of its designation by
Borrower as an Unrestricted Subsidiary. For purposes of determining "fair value"
in this context, a determination by the board of directors of the Borrower or
the applicable Restricted Subsidiary shall be sufficient with regard to
consideration with fair value not exceeding $20,000,000 and the concurrence of
the Administrative Agent shall be required for consideration in excess of
$20,000,000.

          "Restricted Payment" means (a) any dividend or other distribution
           ------------------
(whether in cash, securities or other property) with respect to any shares of
any class of capital stock of the Borrower or any Subsidiary, or any payment
(whether in cash, securities or other property), including any sinking fund or
similar deposit, on account of the purchase, redemption, retirement,
acquisition, cancellation or termination of any such shares of capital stock of
the Borrower or any option, warrant or other right to acquire any such shares of
capital stock of the Borrower, and (b) Restricted Investments.

          "Restricted Subsidiaries" means all Subsidiaries of the Borrower which
           -----------------------
are designated as a Restricted Subsidiary on Schedule 3.12 hereto or pursuant to
Sections 5.09 or 6.13 hereof and which the Borrower has not redesignated as an
Unrestricted Subsidiary pursuant to Section 6.13 hereof.

          "Revolving Loans" means loans made by the Lenders to the Borrower
           ---------------
pursuant to Section 2.01(a).

          "SEC PV-10" means estimated future net revenues from the production of
           ---------
proved oil and gas reserves, net of all production-related taxes, lease
operating expenses and capital costs, discounted by a factor of 10% per annum,
before income taxes and with no price or cost escalation or de-escalation
(except for any contract prices in effect as of the date of the reserve report),
in accordance with guidelines promulgated by the Securities and Exchange
Commission.

          "S&P" means Standard & Poor's.
           ---

          "Statutory Reserve Rate" means a fraction (expressed as a decimal),
           ----------------------
the numerator of which is the number one and the denominator of which is the
number one minus the aggregate of the maximum reserve percentages (including any
marginal, special, emergency or supplemental reserves) expressed as a decimal
established by the Board to which the Administrative Agent is subject, with
respect to the Adjusted LIBO Rate, for eurocurrency funding (currently referred
to as "Eurocurrency Liabilities" in Regulation D of the Board). Such reserve
percentages shall include those imposed pursuant to such Regulation D.
Eurodollar Loans shall be deemed to constitute eurocurrency funding and to be
subject to such reserve requirements without benefit of or credit for proration,
exemptions or offsets that may be available from time to time to any Lender
under such Regulation D or any comparable regulation. The Statutory Reserve Rate
shall be adjusted automatically on and as of the effective date of any change in
any reserve percentage.

                                     -14-
<PAGE>

          "subsidiary" means, with respect to any Person (the "parent") at any
           ----------                                          ------
date, any corporation, limited liability company, partnership, association or
other entity the accounts of which would be consolidated with those of the
parent in the parent's consolidated financial statements if such financial
statements were prepared in accordance with GAAP as of such date.

          "Subsidiary" means any subsidiary of the Borrower.
           ----------

          "Subsidiary Guaranty Agreement" means an agreement executed by each
           -----------------------------
Restricted Subsidiary guarantying, unconditionally, payment of all amounts owing
and to be owing under or in connection with this Agreement, as the same may be
amended, modified or supplemented from time to time.

          "Taxes" has the meaning set forth in Section 2.20(a).
           -----

          "Term Loans" mean outstanding Revolving Loans converted to term loans
           ----------
pursuant to Sections 2.01(e) and 4.03.

          "Transactions" means the execution, delivery and performance by the
           ------------
Borrower of this Agreement, the borrowing of Loans and the use of the proceeds
thereof.

          "Type", when used in reference to any Loan or Borrowing, refers to
           ----
whether the rate of interest on such Loan, or on the Loans comprising such
Borrowing, is determined by reference to the Adjusted LIBO Rate or the Alternate
Base Rate.

          "UNOCAL" means Union Oil Company of California, or any one of its
           ------
successors or any one of its consolidated subsidiaries.

          "Unrestricted Subsidiary" means any Subsidiary other than a Restricted
           -----------------------
Subsidiary.

          "Withdrawal Liability" means liability to a Multiemployer Plan as a
           --------------------
result of a complete or partial withdrawal from such Multiemployer Plan, as such
terms are defined in Part I of Subtitle E of Title IV of ERISA.

          SECTION 1.02.  Terms Generally.  The definitions of terms herein shall
                         ---------------
apply equally to the singular and plural forms of the terms defined. Whenever
the context may require, any pronoun shall include the corresponding masculine,
feminine and neuter forms. The words "include", "includes" and "including" shall
be deemed to be followed by the phrase "without limitation". The word "will"
shall be construed to have the same meaning and effect as the word "shall".
Unless the context requires otherwise (a) any definition of or reference to any
agreement, instrument or other document herein shall be construed as referring
to such agreement, instrument or other document as from time to time amended,
supplemented or otherwise modified (subject to any restrictions on such
amendments, supplements or modifications set forth herein), (b) any reference
herein to any Person shall be construed to include such Person's successors and
assigns, (c) the words "herein", "hereof" and "hereunder", and words of similar
import, shall be construed to refer to this Agreement in its entirety and not to
any particular provision hereof, (d) all references herein to Articles,
Sections, Exhibits and Schedules shall be construed to refer to Articles and
Sections of, and Exhibits and Schedules to, this Agreement and (e) the words
"asset" and "property" shall be construed to have the same meaning and effect
and to refer to any and all tangible and intangible assets and properties,
including cash, securities, accounts and contract rights.

                                     -15-
<PAGE>

          SECTION 1.03.  Accounting Terms; GAAP.  Except as otherwise expressly
                         ----------------------
provided herein, all terms of an accounting or financial nature shall be
construed in accordance with GAAP, as in effect from time to time; provided
                                                                   --------
that, if the Borrower notifies the Administrative Agent that the Borrower
requests an amendment to any provision hereof to eliminate the effect of any
change occurring after the date hereof in GAAP or in the application thereof on
the operation of such provision (or if the Administrative Agent notifies the
Borrower that the Required Lenders request an amendment to any provision hereof
for such purpose), regardless of whether any such notice is given before or
after such change in GAAP or in the application thereof, then such provision
shall be interpreted on the basis of GAAP as in effect and applied immediately
before such change shall have become effective until such notice shall have been
withdrawn or such provision amended in accordance herewith.

                                  ARTICLE II

                                  The Credits
                                  -----------

          SECTION  2.01  Commitments.
                         -----------

          (a)  Revolving Loans.  Subject to the terms and conditions and relying
               ---------------
on the representations and warranties contained herein, each Lender severally
agrees, on any Business Day, to make Revolving Loans to the Borrower during the
Availability Period in an aggregate principal amount at any one time outstanding
up to but not exceeding the amount of such Lender's Commitment as then in
effect; provided, however, that the total Exposures at any one time outstanding
        --------  -------
shall not exceed the total Commitments. There may be more than one Borrowing
with respect to Loans on any Business Day. Within the foregoing limits and
subject to the conditions set out in Article IV, the Borrower may obtain
Borrowings of Loans, repay or prepay such Loans, and reborrow such Loans. Any
portion of each Lender's Commitment not utilized on or before the Conversion
Date shall be permanently cancelled.

          (b)  Types of Loans.  The Loans made pursuant hereto by each Lender
               --------------
shall, at the option of the Borrower, be either ABR Loans or Eurodollar Loans
and may be continued or converted pursuant to Section 2.11, provided that,
except as otherwise specifically provided herein, all Loans made pursuant to the
same Borrowing shall be of the same Type.

          (c)  Commitments.  (i)  Each Lender's Exposure shall not exceed at any
               -----------
one time the amount set forth opposite such Lender's name on Schedule 2.01 under
the caption "Commitment".

          (ii) The Borrower shall have the right, without the consent of the
     Lenders but with the prior approval of the Administrative Agent, not to be
     unreasonably withheld, to cause from time to time an increase in the total
     Commitments of the Lenders by adding to this Agreement one or more
     additional Lenders or by allowing one or more Lenders to increase their
     respective Commitments; provided however (i) no Event of Default shall have
                             -------- -------
     occurred hereunder which is continuing, (ii) no such increase shall result
     in the aggregate Commitments hereunder to exceed $250,000,000, (iii) no
     Lender's Commitment shall be increased without such Lender's consent, and
     (iv) on the effective date of any such increase, there shall be no
     outstanding Eurodollar Loans hereunder.

          (d) Amounts of Borrowings, etc.  The aggregate principal amount of
              --------------------------
each Borrowing (i) of Eurodollar Loans shall be not less than $5,000,000 and
shall be in an integral multiple of $1,000,000, and (ii) of ABR Loans shall be
not less than $1,000,000 and shall be in an integral multiple of $100,000,

                                     -16-
<PAGE>

except that any Borrowing of Loans that are ABR Loans may be in the aggregate
amount of the unused total Commitments in effect at such time.  Borrowings of
more than one Type may be outstanding at the same time; provided, however, that
                                                        --------  -------
the Borrower shall not be entitled to request any Borrowing that, if made, would
result in an aggregate of more than 10 separate Borrowings of Eurodollar Loans
being outstanding at any one time.  For purposes of the foregoing, Borrowings
having different Interest Periods, regardless of whether they commence on the
same date, shall be considered separate Borrowings.

          (e)  Conversion to Term Loans.  The aggregate principal amount of all
               ------------------------
Revolving Loans outstanding immediately prior to the close of the Administrative
Agent's business on the Conversion Date shall automatically convert to Term
Loans maturing on the Final Maturity Date. Any Term Loans that are prepaid may
not be reborrowed.

          SECTION  2.02  Borrowing Requests.
                         ------------------

          (a)  Borrowing Requests.  Whenever the Borrower desires to make a
               ------------------
Borrowing hereunder, it shall give Advance Notice in the form of a Borrowing
Request, specifying, subject to the provisions hereof, (i) the aggregate
principal amount of the Loans to be made pursuant to such Borrowing, (ii) the
date of Borrowing (which shall be a Business Day), (iii) whether the Loans being
made pursuant to such Borrowing are to be ABR Loans or Eurodollar Loans, and
(iv) in the case of Eurodollar Loans, the Interest Period to be applicable
thereto.

          (b)  Notice by Administrative Agent.  The Administrative Agent shall
               ------------------------------
promptly give each Lender facsimile or telephonic notice (and, in the case of
telephonic notices, confirmed by facsimile or otherwise in writing) of the
proposed Borrowing, of such Lender's Percentage Share thereof and of the other
matters covered by the Advance Notice.  Without in any way limiting the
Borrower's obligation to confirm in writing any telephonic notice, the
Administrative Agent may act without liability upon the basis of telephonic
notice believed by the Administrative Agent in good faith to be from the
Borrower prior to receipt of written confirmation.  In each such case, the
Borrower hereby waives the right to dispute the Administrative Agent's record of
the terms of such telephonic notice, absent manifest error.

          SECTION 2.03.  Intentionally Omitted.
                         ---------------------

          SECTION 2.04   Disbursement of Funds.
                         ---------------------

          (a)  Availability.  No later than 2:00 p.m. (Houston time) on the date
               ------------
of each Borrowing, each Lender will make available to the Administrative Agent
such Lender's Percentage Share of the amount (if any) by which the principal
amount of the Borrowing requested to be made on such date exceeds the principal
amount of Loans (if any) maturing on such date, in Dollars and in immediately
available funds at the Payment Office or pursuant to the Borrower's written
instructions to the Administrative Agent. The Administrative Agent will make
available to the Borrower at the Payment Office the aggregate of the amounts (if
any) so made available by the Lenders by depositing such amounts, in immediately
available funds, to an account of the Borrower at the Administrative Agent
designated by the Borrower for such purpose. To the extent that Loans mature on
the date of a requested Borrowing of Loans, the Lenders shall apply the proceeds
of the Loans then being made, to the extent thereof, to the repayment of such
maturing Loans, such Loans intended to be a contemporaneous exchange.

          (b)  Funds to the Administrative Agent.  Unless the Administrative
               ---------------------------------
Agent shall have been notified by any Lender prior to the date of a Borrowing
that such Lender does not intend to make available to the Administrative Agent
such Lender's Percentage Share of the Borrowing to be made on such date, the

                                     -17-
<PAGE>

Administrative Agent may assume that such Lender has made such amount available
to the Administrative Agent on such date, and the Administrative Agent may make
available to the Borrower a corresponding amount. If such corresponding amount
is not in fact made available to the Administrative Agent by such Lender on the
date of a Borrowing, the Administrative Agent shall be entitled to recover such
corresponding amount on demand from such Lender together with interest at the
Federal Funds Effective Rate. If such Lender does not pay such corresponding
amount forthwith upon the Administrative Agent's demand therefor, the
Administrative Agent shall promptly notify the Borrower, and the Borrower shall
immediately pay such corresponding amount to the Administrative Agent together
with interest at the rate specified for the Borrowing which includes such amount
paid. Nothing in this Section shall be deemed to relieve any Lender from its
obligation to fulfill its Commitment hereunder or to prejudice any rights which
the Borrower may have against any Lender as a result of any default by such
Lender hereunder.

          (c)  Lenders' Responsibilities.  No Lender shall be responsible for
               -------------------------
any default by any other Lender in its obligation to make Loans hereunder, and
each Lender shall be obligated to make the Loans provided to be made by it
hereunder, regardless of the failure of any other Lender to fulfill its
Commitment hereunder.

          SECTION  2.05  Notes.  Any Lender may request that Loans made by it
                         -----
be evidenced by a promissory note (individually, a "Note" and collectively,
                                                    ----
"Notes").  In such event, the Borrower shall prepare, execute and deliver to
------
such Lender a promissory note payable to the order of such Lender (or, if
requested by such Lender, to such Lender and its registered assigns) and in a
form approved by the Administrative Agent.  Thereafter, the Loans evidenced by
such promissory note and interest thereon shall at all times (including after
assignment pursuant to Section 10.04) be represented by one or more promissory
notes in such form payable to the order of the payee named therein (or, if such
promissory note is a registered note, to such payee and its registered assigns).

          SECTION  2.06  Interest.  In all cases subject to Section 10.13:
                         --------

          (a)  ABR Loans.  Subject to Section 2.06(c), the Borrower agrees to
               ---------
pay interest in respect of the unpaid principal amount of each ABR Loan from the
date thereof until payment in full thereof at a rate per annum which shall be,
for any day, equal to the sum of the Applicable Rate (ABR Spread) plus the
Alternate Base Rate in effect on such day, but in no event to exceed the Highest
Lawful Rate. If for any reason the Administrative Agent shall have determined
(which determination shall be conclusive and binding, absent manifest error)
that it is unable to ascertain the Federal Funds Effective Rate for any reason,
including but not limited to the inability of the Administrative Agent to obtain
sufficient bids or publications in accordance with the terms hereof, the
Alternate Base Rate shall be the Prime Rate until the circumstances giving rise
to such inability no longer exist.

          (b)  Eurodollar Loans.  Subject to Section 2.06(c), the Borrower
               ----------------
agrees to pay interest in respect of the unpaid principal amount of each
Eurodollar Loan from the date thereof until payment in full thereof at a rate
per annum which shall be the sum of the Applicable Rate (Eurodollar Spread) plus
the relevant Adjusted LIBO Rate, but in no event to exceed the Highest Lawful
Rate.

          (c)  Default Interest.  Overdue principal and, to the extent permitted
               ----------------
by law, overdue interest in respect of each Loan and all other amounts owing
hereunder shall bear interest for each day that such amounts are overdue at a
rate per annum equal to two percent (2%) in excess of the Adjusted LIBO Rate
plus the Applicable Rate or the Alternate Base Rate, as applicable to such Loan,
in effect for each such day, and all other amounts owing hereunder shall bear
interest for each day that such amounts are overdue at a rate

                                     -18-
<PAGE>

per annum equal to two percent (2%) in excess of the Alternate Base Rate, but in
no event shall any such rate exceed the Highest Lawful Rate.

          (d)  Interest Payment Dates.  Interest on each Loan shall accrue from
               ----------------------
and including the date of such Loan to but excluding the date of payment in full
thereof. Interest on each Eurodollar Loan shall be payable on the last day of
each Interest Period applicable thereto and, in the case of an Interest Period
in excess of three months, on each day which occurs every three months after the
initial date of such Interest Period, and on any prepayment (on the amount
prepaid), at maturity (whether by acceleration or otherwise) and, after
maturity, on demand. Interest on ABR Loans shall be payable on each Quarterly
Date, commencing on the first of such days to occur after such Loan is made, at
maturity (whether by acceleration or otherwise) and, after maturity, on demand.

          (e)  Notice by the Administrative Agent.  The Administrative Agent,
               ----------------------------------
upon determining the Adjusted LIBO Rate for any Interest Period, shall promptly
notify by telephone (confirmed in writing) or in writing the Borrower and the
Lenders thereof.

          SECTION  2.07  Interest Periods.  In connection with each Borrowing
                         ----------------
of Eurodollar Loans, the Borrower shall elect an Interest Period to be
applicable to such Borrowing, which Interest Period shall begin on and include,
as the case may be, the date selected by the Borrower as of the date of the
Borrowing pursuant to Section 2.02(a), or at conversion from one Type of Loan to
another pursuant to Section 2.11(e), or the date of expiration of the then
current Interest Period applicable thereto, and end on but exclude the date
which is either one, two, three, six or 12 months thereafter, as selected by the
Borrower; provided that:
          --------

          (a)  Business Days.  If any Interest Period would otherwise expire on
               -------------
a day which is not a Business Day, such Interest Period shall expire on the next
succeeding Business Day, provided, further, that if any Interest Period (other
                         --------  -------
than in respect of a Borrowing of Eurodollar Loans the Interest Period of which
is expiring pursuant to Section 2.15(b) hereof) would otherwise expire on a day
which is not a Business Day but is a day of the month after which no further
Business Day occurs in such month, such Interest Period shall expire on the next
preceding Business Day;

          (b)  Month End.  Any Interest Period which begins on the last Business
               ---------
Day of a calendar month (or on a day for which there is no numerically
corresponding day in the calendar month at the end of such Interest Period)
shall, subject to Section 2.07(c) below, end on the last Business Day of a
calendar month;

          (c)  Payment Limitations.  No Interest Period shall extend beyond any
               -------------------
date that any principal payment or prepayment is scheduled to be due unless the
aggregate principal amount of Borrowings which are Borrowings of ABR Loans or
which have Interest Periods which will expire on or before such date, less the
aggregate amount of any other principal payments or prepayments due during such
Interest Period, is equal to or in excess of the amount of such principal
payment or prepayment; and

          (d)  Maturity Dates.  No Interest Period with regard to Loans shall
               --------------
extend beyond the Final Maturity Date.

          SECTION  2.08  Repayment of Loans.  The Borrower will pay to the
                         ------------------
Administrative Agent for account of each Lender the outstanding principal amount
of each Loan made by such Lender on or before the Final Maturity Date.

                                     -19-
<PAGE>

          SECTION  2.09  Termination or Reduction of Commitments.  The Borrower
                         ---------------------------------------
may, upon at least 10 Business Days' notice to the Administrative Agent,
terminate entirely at any time the unused portions of the Commitments, or
proportionately reduce from time to time by an aggregate amount of $1,000,000 or
any larger multiple thereof, the unused portions of the Commitments, provided
that any such reduction shall apply proportionately to the Commitment of each
Lender. If the Commitments are terminated in their entirety, all accrued
facility fees with respect thereto shall be payable on the effective date of
such termination. The unused portions of the Commitments once terminated or
reduced may not be reinstated.

          SECTION  2.10  Prepayments.
                         -----------

          (a)  Voluntary Prepayments.  The Borrower may, at its option, at any
               ---------------------
time and from time to time, prepay Loans, in whole or in part, without premium
or penalty (other than funding losses, if any, resulting from such prepayment
being made other than on the last day of an Interest Period with respect to any
Eurodollar Loan as provided in Section 2.18), upon giving, in the case of a
Eurodollar Loan, three Business Days' prior written notice to the Administrative
Agent, and, in the case of an ABR Loan, one Business Day's prior written notice
to the Administrative Agent.  Such notice shall be irrevocable and specify the
date and amount of prepayment and the Loan or Loans (including the Type thereof)
to which such prepayment is to be applicable.  The payment amount specified in
such notice shall be due and payable on the date specified.  Each prepayment of
Loans shall be in the minimum principal amount of $1,000,000 or any larger
multiple thereof or the aggregate balance outstanding on the applicable Notes.
Each prepayment made pursuant to this Section shall be subject to Section 2.18
(as applicable) and shall be applied ratably to prepay the Loans of the several
Lenders.

          (b)  Notice by Administrative Agent.  Upon receipt of a notice of
               ------------------------------
prepayment pursuant to this Section, the Administrative Agent shall promptly
notify each Lender of the contents thereof and of such Lender's ratable share of
such prepayment.

          SECTION  2.11  Continuation and Conversion Options.
                         -----------------------------------

          (a)  Continuation.  The Borrower may elect to continue all or any part
               ------------
of any Borrowing of Eurodollar Loans beyond the expiration of the then current
Interest Period relating thereto by giving Advance Notice to the Administrative
Agent of such election, specifying the Eurodollar Loan or portion thereof to be
continued and the Interest Period therefor. In the absence of such a timely and
proper election with regard to Eurodollar Loans, the Borrower shall be deemed to
have elected to convert such Eurodollar Loan to an ABR Loan pursuant to Section
2.11(d).

          (b)  Amounts of Continuations.  All or part of any Eurodollar Loan may
               ------------------------
be continued as provided herein, provided that any continuation of such Loan
shall not result in a Borrowing of Eurodollar Loans in an amount other than
$5,000,000 or an integral multiple of $1,000,000 in excess thereof.

          (c)  Continuation or Conversion Upon Default.  If no Default shall
               ---------------------------------------
have occurred and be continuing, each Eurodollar Loan may be continued or
converted as provided in this Section. If a Default shall have occurred and be
continuing, the Borrower shall not have the option to elect to continue any such
Eurodollar Loan pursuant to Section 2.11(a) or to convert ABR Loans pursuant to
Section 2.11(e).

          (d)  Conversion to Alternate Base Rate.  The Borrower may elect to
               ---------------------------------
convert any Eurodollar Loan on the last day of the then current Interest Period
relating thereto to an ABR Loan by giving Advance Notice to the Administrative
Agent of such election.

                                     -20-
<PAGE>

          (e)  Conversion to Eurodollar Rate.  The Borrower may elect to convert
               -----------------------------
any ABR Loan at any time or from time to time to a Eurodollar Loan by giving
Advance Notice to the Administrative Agent of such election, specifying each
Interest Period therefor.

          (f)  Amounts of Conversions.  All or any part of the outstanding Loans
               ----------------------
may be converted as provided herein, provided that any conversion of such Loans
shall not result in a Borrowing of Eurodollar Loans in an amount other than
$5,000,000 or an integral multiple of $1,000,000 in excess thereof.

          SECTION  2.12. Fees.  (a)  The Borrower agrees to pay to the
                         ----
Administrative Agent for the account of each Lender a facility fee, which shall
accrue at the Applicable Rate (Facility Fee Rate) on the daily amount of the
Commitment of such Lender (whether used or unused) during the period from and
including the Effective Date to but excluding the date on which such Commitment
terminates; provided that, if such Lender continues to have any Exposure after
            --------
its Commitment terminates, then such facility fee shall continue to accrue on
the daily amount of such Lender's Exposure from and including the date on which
its Commitment terminates to but excluding the date on which such Lender ceases
to have any Exposure. Accrued facility fees shall be payable in arrears on the
last day of March, June, September and December of each year and on the date on
which the Commitments terminate, commencing on the first such date to occur
after the date hereof; provided that any facility fees accruing after the date
                       --------
on which the Commitments terminate shall be payable on demand. All facility fees
shall be computed on the basis of a year of 360 days and shall be payable for
the actual number of days elapsed (including the first day but excluding the
last day).

          (b)  The Borrower agrees to pay to the Administrative Agent, for its
own account, fees payable in the amounts and at the times separately agreed upon
between the Borrower and the Administrative Agent.

          (c)  All fees payable hereunder shall be paid on the dates due, in
immediately available funds, to the Administrative Agent for distribution, in
the case of facility fees and participation fees, to the Lenders. Fees paid
shall not be refundable under any circumstances absent manifest error.

          SECTION  2.13  Payments, etc.
                         -------------

          (a)  Without Setoff, etc.  Except as otherwise specifically provided
               -------------------
herein, all payments under this Agreement shall be made to the Administrative
Agent on behalf of the Lenders without defense, set-off or counterclaim to the
Administrative Agent not later than 12:30 p.m. (Houston time) on the date when
due and shall be made in Dollars in immediately available funds at the Payment
Office.  The Administrative Agent will promptly thereafter distribute funds in
the form received relating to the payment of principal or interest or fees
ratably to the Lenders for the account of their respective Lending Offices, and
funds in the form received relating to the payment of any other amount payable
to any Lender to such Lender for the account of its Lending Office.

          (b)  Non-Business Days.  Whenever any payment to be made hereunder or
               -----------------
under any Note or any report or information to be delivered hereunder shall be
stated to be due on a day which is not a Business Day, the due date thereof
shall be extended to the next succeeding Business Day (except as otherwise
provided in Section 2.07) and, with respect to payments of principal, interest
thereon shall be payable at the applicable rate during such extension.

          (c)  Computations.  All computations of interest shall be made on the
               ------------
basis of a year of 360 days (unless such calculation would result in a usurious
rate, in which case interest shall be calculated on

                                     -21-
<PAGE>

the basis of a year of 365 or 366 days, as the case may be) in the case of
Eurodollar Loans, and 365 or 366 days (as the case may be) in the case of ABR
Loans, and all computations of fees shall be made on the basis of a year of 360
days (unless such calculation would result in a usurious rate, in which case
interest shall be calculated on the basis of a year of 365 or 366 days, as the
case may be), in each case for the actual number of days (including the first
day but excluding the last day) occurring in the period for which such interest
or fees are payable. Each determination by the Administrative Agent of an
interest rate or fee hereunder shall, except for manifest error, be final,
conclusive and binding for all purposes, provided that such determination shall
be made in good faith in a manner generally consistent with the Administrative
Agent's standard practice. If the Administrative Agent and the Borrower
determine that manifest error exists, such parties shall correct such error by
way of an adjustment to the payment due on the next Quarterly Date.

          SECTION  2.14  Interest Rate Not Ascertainable, etc.  In the event
                         ------------------------------------
that the Administrative Agent shall have determined (which determination shall
be reasonably exercised and shall, absent manifest error, be final, conclusive
and binding upon all parties) that on any date for determining the Eurodollar
Rate for any Interest Period, by reason of any changes arising after the date of
this Agreement affecting the interbank Eurodollar market, or any Lender's
position in such market, adequate and fair means do not exist for ascertaining
the applicable interest rate on the basis provided for in the definition of
Eurodollar Rate, then, and in any such event, the Administrative Agent shall
forthwith give notice (by telephone confirmed in writing) to the Borrower and to
the Lenders of such determination.  Until the Administrative Agent notifies the
Borrower that the circumstances giving rise to the suspension described herein
no longer exist, the obligations of the Lenders to make Eurodollar Loans shall
be immediately suspended; any Eurodollar Loan that is requested (by
continuation, conversion or otherwise) shall instead be made as an ABR Loan, and
any outstanding Eurodollar Loan shall be converted, on the last day of the then
current Interest Period applicable thereto, to an ABR Loan.

          SECTION  2.15  Illegality.
                         ----------

          (a)  Determinations of Illegality.  In the event that any Lender
               ----------------------------
shall have determined (which determination shall be reasonably exercised and
shall, absent manifest error, be final, conclusive and binding upon all parties)
at any time that the making or continuance of any Eurodollar Loan has become
unlawful due to the introduction of or any change in or in the interpretation of
any applicable law, governmental rule, regulation, guideline or order (whether
or not having the force of law and whether or not failure to comply therewith
would be unlawful), then, in any such event, the Lender shall give prompt notice
(by telephone confirmed in writing) to the Administrative Agent of such
determination (which notice the Administrative Agent shall promptly transmit to
the Borrower and the other Lenders).

          (b)  Eurodollar Loans Suspended.  Upon the giving of the notice to the
               --------------------------
Borrower referred to in Section (a) above, (i) the Borrower's right to request
(by continuation, conversion or otherwise) and such Lender's obligation to make
Eurodollar Loans shall be immediately suspended, and any such requested
Eurodollar Loan shall instead be made as an ABR Loan, and (ii) if the affected
Eurodollar Loan or Loans are then outstanding, the Borrower shall immediately,
or if permitted by applicable law, no later than the date permitted thereby,
upon at least one Business Day's written notice to the Administrative Agent and
the affected Lender, convert each such Eurodollar Loan into an ABR Loan,
provided that if more than one Lender is affected at any time, then all affected
Lenders must be treated the same pursuant to this Section.

                                     -22-
<PAGE>

          SECTION  2.16  Increased Costs.
                         ---------------

          (a)  Eurodollar Regulations, etc.  If, by reason of (x) after the date
               ---------------------------
hereof, the introduction of or any change (including, but not limited to, any
change by way of imposition or increase of reserve requirements) in or in the
interpretation of any law or regulation, or (y) the compliance with any
guideline or request made after the date hereof by any central bank or other
governmental authority or quasi-governmental authority exercising control over
banks or financial institutions generally (whether or not having the force of
law):

               (i)  any Lender (or its applicable Lending Office) shall be
     subject to any tax, duty or other charge with respect to its Eurodollar
     Loans or its obligation to make Eurodollar Loans, or shall change the basis
     of taxation of payments to any Lender of the principal of or interest on
     its Eurodollar Loans or its obligation to make Eurodollar Loans (except for
     changes in the rate of tax on the overall net income or gross receipts of
     such Lender or its applicable Lending Office imposed by the jurisdiction in
     which such Lender's principal executive office or applicable Lending Office
     is located); or

               (ii) any reserve (including, but not limited to, any imposed by
     the Board of Governors of the Federal Reserve System), special deposit or
     similar requirement against assets of, deposits with or for the account of,
     or credit extended by, any Lender's applicable Lending Office shall be
     imposed or deemed applicable or any other condition affecting its
     Eurodollar Loans or its obligations to make Eurodollar Loans shall be
     imposed on any Lender or its applicable Lending Office or the interbank
     Eurodollar market or the secondary certificate of deposit market;

     and as a result thereof there shall be any increase in the cost to such
     Lender of agreeing to make or making, funding or maintaining Eurodollar
     Loans (except to the extent already included in the determination of the
     applicable Eurodollar Rate) or there shall be a reduction in the amount
     received or receivable by such Lender or its applicable Lending Office,
     then the Borrower shall from time to time, upon written notice from and
     demand by such Lender (with a copy of such notice and demand to the
     Administrative Agent), pay to such Lender, within 30 days after the date
     specified in such notice and demand, additional amounts determined by such
     Lender in a reasonable manner to be sufficient to indemnify such Lender
     against such increased cost.  A certificate as to the amount of such
     increased cost and the calculation thereof, submitted to the Borrower and
     the Administrative Agent by such Lender, shall, except for manifest error,
     be final, conclusive and binding for all purposes, provided that the
     determination of such amount shall be made in good faith in a manner
     generally consistent with such Lender's standard practice.

          (b)  Costs.  If any Lender shall advise the Administrative Agent that
               -----
at any time, because of the circumstances described in clauses (x) or (y) in
Section 2.16(a) or any other circumstances arising after the Effective Date
affecting such Lender or the interbank Eurodollar market or such Lender's
position in such market, the Eurodollar Rate, as determined in good faith by the
Administrative Agent, will not adequately and fairly reflect the cost to such
Lender of funding its Eurodollar Loans, then, and in any such event:

               (i)  the Administrative Agent shall forthwith give notice (by
     telephone confirmed in writing) to the Borrower and to the Lenders of such
     advice; and

               (ii) the Borrower's right to request and such Lender's
     obligation to make Eurodollar Loans shall be immediately suspended, any
     such Eurodollar Loan that is requested (by continuation, conversion or
     otherwise) shall instead be made as an ABR Loan, and any such outstanding

                                     -23-
<PAGE>

     Eurodollar Loan shall be converted, on the last day of the then current
     Interest Period applicable thereto, to an ABR Loan.

          (c)  Capital Adequacy.  If, by reason of (i) after the date hereof,
               ----------------
the introduction of or any change (including, but not limited to, any change by
way of imposition or increase of reserve requirements) in or in the
interpretation of any law or regulation, or (ii) the compliance with any
guideline or request made after the date hereof by any central bank or other
governmental authority or quasi-governmental authority exercising control over
banks or financial institutions generally (whether or not having the force of
law) affects or would affect the amount of capital required to be maintained by
any Lender or any corporation controlling such Lender, and the amount of such
capital is increased by or based upon the existence of such Lender's Commitment
to lend hereunder and other commitments of this type, then, within 30 days after
written request therefor by such Lender (with a copy of such request to the
Administrative Agent), the Borrower shall pay to such Lender, from time to time
as specified by such Lender, additional amounts sufficient to compensate such
Lender for the increased cost of such additional capital in light of such
circumstances, to the extent that such Lender reasonably determines such
increase in capital to be allocable to the existence of such Lender's Commitment
to lend hereunder.  A certificate as to such amounts and the calculation
thereof, submitted to the Borrower and the Administrative Agent by such Lender,
shall be conclusive and binding for all purposes, absent manifest error,
provided that the determination of such amount shall be made in good faith in a
manner generally consistent with such Lender's standard practice.

          (d)  Notice.  The Borrower shall not be obligated to compensate any
               ------
Lender pursuant to this Section 2.16 for any amounts attributable to a period
more than 90 days prior to the giving of notice by such Lender to the Borrower
of its intention to seek compensation under this Section 2.16.

          SECTION  2.17  Change of Lending Office.  Each Lender agrees that it
                         ------------------------
will use reasonable efforts to designate an alternate Lending Office with
respect to any of its Eurodollar Loans affected by the matters or circumstances
described in Sections 2.14, 2.15 or 2.16 to reduce the liability of the Borrower
or avoid the results provided thereunder, so long as such designation is not
disadvantageous to such Lender as determined by such Lender in its sole
discretion.

          SECTION  2.18  Funding Losses.  The Borrower shall compensate each
                         --------------
Lender, upon its written request (which request shall set forth the basis for
requesting such amounts and which request shall be reasonably exercised and
shall, absent manifest error, be final, conclusive and binding upon all of the
parties hereto), for all losses, expenses and liabilities (including, but not
limited to, any interest paid by such Lender to lenders of funds borrowed by it
to make or carry its Eurodollar Loans to the extent not recovered by the Lender
in connection with the re-employment of such funds and including loss of
anticipated profits), which the Lender may sustain (i) if for any reason (other
than a default by such Lender) a Borrowing of Eurodollar Loans does not occur on
the date specified therefor in a Borrowing Request (whether or not withdrawn),
(ii) if any repayment (or conversion pursuant to Section 2.15 or otherwise) of
any of its Eurodollar Loans occurs on a date which is not the last day of an
Interest Period applicable thereto, or (iii) if, for any reason, the Borrower
defaults in its obligation to repay its Eurodollar Loans when required by the
terms of this Agreement.

          SECTION  2.19  Sharing of Payments, etc.  If any Lender shall obtain
                         ------------------------
any payment or reduction (including, but not limited to, any amounts received as
adequate protection of a deposit treated as cash collateral under the Bankruptcy
Code) of any obligation of the Borrower hereunder (whether voluntary,
involuntary, through the exercise of any right of set-off, or otherwise) in
excess of its ratable share of payments or reductions on account of such
obligations obtained by all the Lenders, such Lender shall forthwith (i) notify
each of the other Lenders and the Administrative Agent of such receipt, and (ii)
purchase

                                     -24-
<PAGE>

from the other Lenders such participations in the affected obligations as shall
be necessary to cause such purchasing Lender to share the excess payment or
reduction, net of costs incurred in connection therewith, ratably with each of
them, provided that if all or any portion of such excess payment or reduction is
thereafter recovered from such purchasing Lender or additional costs are
incurred, the purchase shall be rescinded and the purchase price restored to the
extent of such recovery or such additional costs, but without interest. The
Borrower agrees that any Lender so purchasing a participation from another
Lender pursuant to this Section may, to the fullest extent permitted by law,
exercise all its rights of payment (including the right of set-off) with respect
to such participation as fully as if such Lender were the direct creditor of the
Borrower in the amount of such participation.

          SECTION 2.20  Taxes.
                        -----

          (a)  Payments Free and Clear. Any and all payments by the Borrower
               -----------------------
under this Agreement or any other Financing Document shall be made, in
accordance with Section 2.13, free and clear of and without deduction for any
and all present or future taxes, levies, imposts, deductions, charges or
withholdings, and all liabilities with respect thereto, excluding, in the case
                                                        ---------
of each Lender and the Administrative Agent, taxes imposed on or measured by its
income or receipts, and franchise or similar taxes imposed on it, by (i) any
jurisdiction (or political subdivision thereof) of which the Administrative
Agent or such Lender, as the case may be, is a citizen or resident or in which
such Lender has a permanent establishment (or is otherwise engaged in the active
conduct of its banking business through an office or a branch) which is such
Lender's applicable Lending Office, (ii) the jurisdiction (or any political
subdivision thereof) in which the Administrative Agent or such Lender is
organized, or (iii) any jurisdiction (or political subdivision thereof) in which
such Lender or the Administrative Agent is presently doing business which taxes
are imposed solely as a result of doing business in such jurisdiction (all such
non-excluded taxes, levies, imposts, deductions, charges, withholdings and
liabilities so arising out of payments by the Borrower being hereinafter
referred to as "Taxes"). If the Borrower shall be required by law to deduct any
                -----
Taxes from or in respect of any sum payable hereunder to the Lenders or the
Administrative Agent (i) the sum payable shall be increased by the amount
necessary so that after making all required deductions (including deductions
applicable to additional sums payable under this Section 2.20) such Lender or
the Administrative Agent (as the case may be) shall receive an amount equal to
the sum it would have received had no such deductions been made, (ii) the
Borrower shall make such deductions, and (iii) the Borrower shall pay the full
amount deducted to the relevant taxing authority or other Governmental Authority
in accordance with applicable law.

          (b)  Other Taxes. In addition, the Borrower agrees to pay to the
               -----------
relevant Governmental Authority any present or future stamp or documentary taxes
or any other excise or property taxes, charges or similar levies that arise from
any payment made hereunder or from the execution, delivery or registration of,
or otherwise with respect to, this Agreement, any Assignment and Acceptance or
any other Loan Document (hereinafter referred to as "Other Taxes").
                                                     -----------

          (c)  Indemnification. The Borrower will indemnify each Lender and the
               ---------------
Administrative Agent for the full amount of Taxes and Other Taxes (including,
but not limited to, any Taxes or Other Taxes imposed by any jurisdiction on
amounts payable under this Section 2.20) paid by such Lender or the
Administrative Agent (on their behalf or on behalf of any Lender), as the case
may be, and any liability (including penalties, interest and expenses) arising
therefrom or with respect thereto, whether or not such Taxes or Other Taxes were
correctly or legally asserted, which are paid or arise no more than 90 days
prior to written demand therefor by such Lender or the Administrative Agent. Any
payment pursuant to such indemnification shall be made within 30 days after the
date any Lender or the Administrative Agent, as the case may be, makes written
demand therefor. If any Lender or the Administrative Agent receives a refund or
credit in respect of any Taxes or Other Taxes for which such Lender or the
Administrative Agent has

                                     -25-
<PAGE>

received payment from the Borrower hereunder it shall promptly notify the
Borrower of such refund or credit and shall, as promptly as reasonably
practicable, pay an amount equal to such refund or credit to the Borrower
without interest (but with any interest so refunded or credited), provided that
the Borrower, upon the request of such Lender or the Administrative Agent,
agrees to return such refund or credit (plus penalties, interest or other
charges) to such Lender or the Administrative Agent in the event such Lender or
the Administrative Agent is required to repay such refund or credit.

          (d)  Receipts. Within 30 days after the date of any payment of Taxes
               --------
or Other Taxes withheld by the Borrower in respect of any payment to any Lender
or the Administrative Agent, the Borrower will furnish to the Administrative
Agent the original or a certified copy of a receipt evidencing payment thereof.

          (e)  Survival. Without prejudice to the survival of any other
               --------
agreement contained herein, the agreements and obligations contained in this
Section 2.20 shall survive the payment in full of principal and interest
hereunder.

          (f)  Lender Representations. Each Lender represents that it is either
               ----------------------
(i) a corporation organized under the laws of the United States of America or
any state thereof or (ii) entitled to complete exemption from United States
withholding tax imposed on or with respect to any payments, including fees, to
be made to it pursuant to this Agreement (A) under an applicable provision of a
tax convention to which the United States of America is a party or (B) because
it is acting through a branch, agency or office in the United States of America
and any payment to be received by it hereunder is effectively connected with a
trade or business in the United States of America. Each Lender that is not a
corporation organized under the laws of the United States of America or any
state thereof agrees to provide to the Borrower and the Administrative Agent on
the Effective Date, or on the date of its delivery of the Assignment and
Acceptance pursuant to which it becomes a Lender, and at such other times as
required by United States law or as the Borrower or the Administrative Agent
shall reasonably request, two accurate and complete original signed copies of
either (A) Internal Revenue Service Form 4224 (or successor form) certifying
that all payments to be made to it hereunder will be effectively connected to a
United States trade or business (the "Form 4224 Certification") or (B) Internal
                                      -----------------------
Revenue Service Form 1001 (or successor form) certifying that it is entitled to
the benefit of a provision of a tax convention to which the United States of
America is a party which completely exempts from United States withholding tax
all payments to be made to it hereunder (the "Form 1001 Certification"). In
                                              -----------------------
addition, each Lender agrees that if it previously filed a Form 4224
Certification it will deliver to the Borrower and the Administrative Agent a new
Form 4224 Certification prior to the first payment date occurring in each of its
subsequent taxable years; and if it previously filed a Form 1001 Certification,
it will deliver to the Borrower and the Administrative Agent a new certification
prior to the first payment date falling in the third year following the previous
filing of such certification. Each Lender also agrees to deliver to the Borrower
and the Administrative Agent such other or supplemental forms as may at any time
be required as a result of changes in applicable law or regulation in order to
confirm or maintain in effect its entitlement to exemption from United States
withholding tax on any payments hereunder, provided that the circumstances of
                                           --------
the Lender at the relevant time and applicable laws permit it to do so. If a
Lender determines, as a result of any change in either (i) applicable law,
regulation or treaty, or in any official application thereof or (ii) its
circumstances, that it is unable to submit any form or certificate that it is
obligated to submit pursuant to this Section, or that it is required to withdraw
or cancel any such form or certificate previously submitted, it shall promptly
notify the Borrower and the Administrative Agent of such fact. If a Lender is
organized under the laws of a jurisdiction outside the United States of America,
unless the Borrower and the Administrative Agent have received a Form 1001
Certification or Form 4224 Certification satisfactory to them indicating that
all payments to be made to such Lender hereunder are not subject to United
States withholding tax, the Borrower shall withhold taxes from such payments at
the

                                     -26-
<PAGE>

applicable statutory rate, provided that such withholding shall not increase the
amount of payments for the account of such Lender to be made by the Borrower
pursuant to Section 2.20(a). Each Lender agrees to indemnify and hold harmless
from any United States taxes, penalties, interest and other expenses, costs and
losses incurred or payable by (i) the Administrative Agent as a result of such
Lender's failure to submit any form or certificate that it is required to
provide pursuant to this Section or (ii) the Borrower or the Administrative
Agent as a result of their reliance on any such form or certificate which it has
provided to them pursuant to this Section.

          (g)  Efforts to Avoid or Reduce. Any Lender claiming any additional
               --------------------------
amounts payable pursuant to this Section 2.20 shall use reasonable efforts
(consistent with legal and regulatory restrictions) to file any certificate or
document requested by the Borrower or the Administrative Agent or to change the
jurisdiction of its applicable Lending Office or to contest any tax imposed if
the making of such a filing or change or contesting such tax would avoid the
need for or reduce the amount of any such additional amounts that may thereafter
accrue and would not, in the sole determination of such Lender, be otherwise
disadvantageous to such Lender.

          SECTION 2.21  Pro Rata Treatment. Except as required under Section
                        ------------------
2.15, 2.16 or 2.18, each Borrowing, each payment or prepayment of principal of
any Borrowing, each payment of interest on the Loans, each payment of the fees,
each reduction of the Commitments, and each refinancing of any Borrowing with,
conversion of any Borrowing to or continuation of any Borrowing as a Borrowing
of any Type shall be allocated ratably and pro rata among the Lenders in
accordance with their respective Percentage Shares. Each Lender agrees that in
computing such Lender's portion of any Borrowing to be made hereunder, the
Administrative Agent may, in its discretion, round each Lender's portion of such
Borrowing to the next higher or lower whole dollar amount.

          SECTION 2.22  Replacement Lenders. If any Lender elects to pass
                        -------------------
through to the Borrower any charge, cost or tax under Sections 2.16 or 2.20 or
terminates the availability of Eurodollar Loans for any period of time under
Sections 2.14 or 2.15, the Borrower may elect to terminate such Lender as a
party to this Agreement; provided that, prior to or concurrently with such
                         --------
termination, if an Event of Default has occurred which is continuing, the
Borrower must receive the consent of the Administrative Agent and either (i) pay
to the terminated Lender all principal, interest, fees, costs and other
Obligations owed to such Lender and accrued though the date of termination and
terminate such Lender's Commitment to make Advances hereunder, in which event
the total Commitments shall be reduced by the Commitment of the terminated
Lender, or (ii) arrange for one or more Eligible Transferees to purchase the
rights and duties of the terminated Lender pursuant to Section 10.04, in which
event the terminated Lender will assign all of such rights and duties to such
Eligible Transferees without recourse, representation or warranty.

                                  ARTICLE III

                        Representations and Warranties
                        ------------------------------

          The Borrower represents and warrants to the Lenders that:

          SECTION 3.01. Organization; Powers. Each of the Borrower and its
                        --------------------
Restricted Subsidiaries is duly organized, validly existing and in good standing
under the laws of the jurisdiction of its organization, has all requisite
corporate power and authority to carry on its business as now conducted and,
where the failure to do so, individually or in the aggregate, would reasonably
be expected to result in a Material

                                     -27-
<PAGE>

Adverse Effect, is qualified to do business in, and is in good standing in,
every jurisdiction where such qualification is required.

          SECTION 3.02.  Authorization; Enforceability. The Transactions are
                         -----------------------------
within the Borrower's corporate powers and have been duly authorized by all
necessary corporate action. This Agreement has been duly executed and delivered
by the Borrower and constitutes a legal, valid and binding obligation of the
Borrower, enforceable in accordance with its terms, subject to applicable
bankruptcy, insolvency, reorganization, moratorium or other laws affecting
creditors' rights generally and subject to general principles of equity,
regardless of whether considered in a proceeding in equity or at law.

          SECTION 3.03.  Governmental Approvals; No Conflicts. The Transactions
                         ------------------------------------
(a) do not require any consent or approval of, registration or filing with, or
any other action by, any Governmental Authority or other Person, except such as
have been obtained or made and are in full force and effect, (b) will not
violate any applicable law or regulation or the charter, by-laws or other
organizational documents of the Borrower or any of its Restricted Subsidiaries
or any order of any Governmental Authority, (c) will not violate or result in a
default under any indenture, agreement or other instrument binding upon the
Borrower or any of its Restricted Subsidiaries or its assets, or give rise to a
right thereunder to require any payment to be made by the Borrower or any of its
Restricted Subsidiaries, and (d) will not result in the creation or imposition
of any Lien on any asset of the Borrower or any of its Restricted Subsidiaries.

          SECTION 3.04.  Financial Condition; No Material Adverse Effect. (a)
                         -----------------------------------------------
The Borrower has heretofore furnished to the Lenders its consolidated balance
sheet and statements of income, stockholders equity and cash flows (i) as of and
for the fiscal year ended December 31, 1999, reported on by KPMG, independent
public accountants, and (ii) as of and for the fiscal quarter and the portion of
the fiscal year ended June 30, 2000, certified by its chief financial officer.
Such financial statements present fairly, in all material respects, the
financial position and results of operations and cash flows of the Borrower and
its consolidated Subsidiaries as of such dates and for such periods in
accordance with GAAP, subject to year-end audit adjustments and the absence of
footnotes in the case of the statements referred to in clause (ii) above.

          (b)  Since June 30, 2000, there has been No Material Adverse Effect.

          SECTION 3.05.  Properties.  (a)  Each of the Borrower and its
                         ----------
Restricted Subsidiaries has indefeasible title to, or valid leasehold interests
in, all of its real and personal property material to its business, except for
defects in title that do not interfere with its ability to conduct its business
as currently conducted or to utilize such properties for their intended
purposes, free and clear of all Liens except Liens permitted by Section 6.02.

          (b)  Each of the Borrower and its Restricted Subsidiaries owns (free
and clear of all Liens except Liens permitted by Section 6.02), or is licensed
to use, all trademarks, tradenames, copyrights, patents and other intellectual
property material to its business, and the use thereof by the Borrower and its
Restricted Subsidiaries does not infringe upon the rights of any other Person,
which, individually or in the aggregate, would reasonably be expected to result
in a Material Adverse Effect.

          SECTION 3.06.  Litigation and Environmental Matters. (a) There are no
                         ------------------------------------
actions, suits or proceedings by or before any arbitrator or Governmental
Authority pending against or, to the knowledge of the Borrower, threatened
against or affecting the Borrower or any of its Subsidiaries which would,
individually or in the aggregate, result in a Material Adverse Effect (other
than the Disclosed Matters).

                                     -28-
<PAGE>

          (b)  Except for the Disclosed Matters, neither the Borrower nor any of
its Subsidiaries (i) has failed to comply with any Environmental Law or to
obtain, maintain or comply with any permit, license or other approval required
under any Environmental Law, (ii) has become subject to any Environmental
Liability, (iii) has received notice of any claim with respect to any
Environmental Liability or (iv) knows of any basis for any Environmental
Liability, which would individually or in the aggregate result in a Material
Adverse Effect.

          SECTION 3.07.  Compliance with Laws and Agreements. Each of the
                         -----------------------------------
Borrower and its Restricted Subsidiaries is in compliance with all laws,
regulations and orders of any Governmental Authority applicable to it or its
property and all indentures, agreements and other instruments binding upon it or
its property, where the failure to do so, individually or in the aggregate,
would reasonably be expected to result in a Material Adverse Effect. No Default
has occurred and is continuing.

          SECTION 3.08.  Investment and Holding Company Act Status. Neither the
                         -----------------------------------------
Borrower nor any of its Subsidiaries is (a) an "investment company" as defined
in, or subject to regulation under, the Investment Company Act of 1940 or (b) a
"holding company" as defined in, or subject to regulation under, the Public
Utility Holding Company Act of 1935.

          SECTION 3.09.  Taxes. Each of the Borrower and its Restricted
                         -----
Subsidiaries has timely filed or caused to be filed all Tax returns and reports
required to have been filed and has paid or caused to be paid all Taxes required
to have been paid by it to the extent that the failure to do so would reasonably
be expected to result in a Material Adverse Effect, except Taxes that are being
contested in good faith by appropriate proceedings and for which the Borrower or
such Restricted Subsidiary, as applicable, has set aside on its books adequate
reserves.

          SECTION 3.10.  ERISA. No ERISA Event has occurred or is reasonably
                         -----
expected to occur that, when taken together with all other such ERISA Events for
which liability is reasonably expected to occur, would reasonably be expected to
result in a Material Adverse Effect.

          SECTION 3.11.  Disclosure. Neither the Information Memorandum dated
                         ----------
September, 2000, nor any of the other reports, financial statements,
certificates or other information furnished by or on behalf of the Borrower to
the Administrative Agent or any Lender in connection with the negotiation of
this Agreement or delivered hereunder (as modified or supplemented by other
information so furnished) contains any material misstatement of fact or omits to
state any material fact necessary to make the statements therein, in the light
of the circumstances under which they were made, not misleading (other than
industry-wide risks normally associated with the types of business conducted by
the Borrower); provided that, with respect to projected financial information
               --------
and reserve evaluations, the Borrower represents only that such information was
prepared in good faith based upon assumptions believed to be reasonable at the
time.

          SECTION 3.12.  Subsidiaries. As of the Effective Date, Borrower has
                         ------------
no Subsidiaries other than those listed on Schedule 3.12 hereto. As of the
Effective Date, Schedule 3.12 sets forth the jurisdiction of incorporation or
organization of each such Subsidiary, the percentage of Borrower's ownership of
the outstanding Equity Interests of each Subsidiary directly owned by Borrower,
and the percentage of each Subsidiary's ownership of the outstanding Equity
Interests of each other Subsidiary. All of the outstanding Equity Interests of
Borrower and each Subsidiary has been validly issued, are fully paid, and
nonassessable. Except as reflected in the Borrower's financial statements
delivered to the Agent and filings with the Securities and Exchange Commission
as of the time this representation is made or deemed made, there are no
outstanding subscriptions, options, warrants, calls, or rights (including
preemptive rights) to acquire, and

                                     -29-
<PAGE>

no outstanding securities or instruments convertible into any Equity Interests
of the Borrower or any Subsidiary. Schedule 3.12 also designates all Restricted
Subsidiaries existing on the Effective Date.

          SECTION 3.13.  Margin Securities. Neither the Borrower nor any
                         -----------------
Restricted Subsidiary is engaged principally, or as one of its important
activities, in the business of extending credit for the purpose of purchasing or
carrying margin stock (within the meaning of Regulations U or X of the Board of
Governors of the Federal Reserve System), and no part of the proceeds of any
Loan will be used to purchase or carry any margin stock or to extend credit to
others for the purpose of purchasing or carrying margin stock in violation of
said Regulations U or X.

                                  ARTICLE IV

                                  Conditions
                                  ----------

          SECTION 4.01.  Effective Date. The obligations of the Lenders to make
                         --------------
Loans hereunder shall not become effective until the date on which each of the
following conditions is satisfied (or waived in accordance with Section 9.02):

          (a)  The Administrative Agent (or its counsel) shall have received
from each party hereto either (i) a counterpart of this Agreement signed on
behalf of such party or (ii) written evidence satisfactory to the Administrative
Agent (which may include telecopy transmission of a signed signature page of
this Agreement) that such party has signed a counterpart of this Agreement.

          (b)  The Administrative Agent shall have received a favorable written
opinion (addressed to the Administrative Agent and the Lenders and dated the
Effective Date) of Thompson & Knight, L.L.P., counsel for the Borrower,
substantially in the form of Exhibit C. The Borrower hereby requests such
counsel to deliver such opinion.

          (c)  The Administrative Agent shall have received such documents and
certificates as the Administrative Agent or its counsel may reasonably request
relating to the organization, existence and good standing of the Borrower, the
authorization of the Transactions and any other legal matters relating to the
Borrower, this Agreement or the Transactions, all in form and substance
satisfactory to the Administrative Agent and its counsel.

          (d)  The Administrative Agent shall have received a certificate, dated
the Effective Date and signed by the President, a Vice President or a Financial
Officer of the Borrower, confirming compliance with the conditions set forth in
paragraphs (a) and (b) of Section 4.02.

          (e)  The Administrative Agent shall have received all fees and other
amounts due and payable on or prior to the Effective Date, including, to the
extent invoiced, reimbursement or payment of all out-of-pocket expenses required
to be reimbursed or paid by the Borrower hereunder.

          (f)  The Existing Titan Credit Facility shall have been fully and
finally paid.

          (g)  The results of a search of the Uniform Commercial Code (or
equivalent) filings made with respect to the Loan Parties in all applicable
jurisdictions evidencing, to the reasonable satisfaction of the Administrative
Agent, that the Liens indicated by such financing statements or similar
documents (if any) are permitted by Section 6.02 or have been released or will
be released on the Effective Date.

                                     -30-
<PAGE>

          (h)  The Administrative Agent shall have received releases of all
Liens securing the Existing Titan Credit Facility duly and validly executed and
in recordable form.

          (i)  The Administrative Agent shall have received a duly executed
Subsidiary Guaranty Agreement from each Restricted Subsidiary in the form of
Exhibit D.

          (j)  The 5-Year Revolving Credit Facility shall be closed
contemporaneously with the closing of this Agreement.

The Administrative Agent shall notify the Borrower and the Lenders of the
Effective Date, and such notice shall be conclusive and binding.

          SECTION 4.02.  Each Credit Event. The obligation of each Lender to
                         -----------------
make a Loan on the occasion of any Borrowing is subject to the satisfaction of
the following conditions:

          (a)  The representations and warranties of the Borrower set forth in
this Agreement shall be true and correct on and as of the date of such
Borrowing.

          (b)  At the time of and immediately after giving effect to such
Borrowing, no Default shall have occurred and be continuing.

Each Borrowing shall be deemed to constitute a representation and warranty by
the Borrower on the date thereof as to the matters specified in paragraphs (a)
and (b) of this Section.

          SECTION 4.03.  Conversion. The occurrence of the Conversion and the
                         ----------
obligation of the Lenders to convert the Revolving Loans outstanding on the
Conversion Date into Term Loans shall be subject to the following:

          (a)  The representations and warranties of the Borrower set forth in
this Agreement and the other Loan Documents shall be true and correct in all
material respects on and as of the Conversion Date (unless such representations
and warranties are stated to relate to a specific earlier date, in which case
such representations and warranties shall be true and correct as of such earlier
date).

          (b)  At the time of and immediately after giving effect to the
Conversion no Default shall have occurred and be continuing.

          (c)  The Administrative Agent shall have received a certificate, dated
the Effective Date and signed by a Financial Officer of the Borrower, confirming
compliance with the conditions set forth above in this Section 4.03.

The Conversion of the Revolving Loans to Term Loans shall be deemed to
constitute a representation and warranty by the Borrower on the date thereof as
to the matters specified in paragraphs (a) and (b) of this Section.

                                     -31-

<PAGE>

                                   ARTICLE V

                             Affirmative Covenants
                             ---------------------

          Until the Commitments have expired or been terminated and the
principal of and interest on each Loan and all fees payable hereunder shall have
been paid in full, the Borrower covenants and agrees with the Lenders that:

          SECTION 5.01.  Financial Statements and Other Information. The
                         ------------------------------------------
Borrower will furnish to the Administrative Agent and each Lender:

          (a)  within 90 days after the end of each fiscal year of the Borrower,
its audited consolidated balance sheet and related statements of operations,
stockholders' equity and cash flows as of the end of and for such year, setting
forth in each case in comparative form the figures for the previous fiscal year,
all reported on by independent public accountants of recognized national
standing (without a "going concern" or like qualification or exception)
acceptable to Administrative Agent to the effect that such consolidated
financial statements present fairly in all material respects the financial
condition and results of operations of the Borrower and its consolidated
Subsidiaries on a consolidated basis in accordance with GAAP consistently
applied;

          (b)  within 45 days after the end of each of the first three fiscal
quarters of each fiscal year of the Borrower, its consolidated balance sheet and
related statements of operations, stockholders' equity and cash flows as of the
end of and for such fiscal quarter and the then elapsed portion of the fiscal
year, setting forth in each case in comparative form the figures for the
corresponding period or periods of (or, in the case of the balance sheet, as of
the end of) the previous fiscal year, all certified by one of its Financial
Officers as presenting fairly in all material respects the financial condition
and results of operations of the Borrower and its consolidated Subsidiaries on a
consolidated basis in accordance with GAAP consistently applied, subject to
normal year-end audit adjustments and the absence of footnotes;

          (c)  concurrently with any delivery of financial statements under
clause (a) or (b) above, a certificate of a Financial Officer of the Borrower
(i) certifying as to whether a Default has occurred and, if a Default has
occurred, specifying the details thereof and any action taken or proposed to be
taken with respect thereto, (ii) setting forth reasonably detailed calculations
demonstrating compliance with Sections 7.01 and 7.02 and (iii) stating whether
any change in GAAP or in the application thereof has occurred since the date of
the audited financial statements referred to in Section 3.04 and, if any such
change has occurred, specifying the effect of such change on the financial
statements accompanying such certificate;

          (d)  promptly after the same become publicly available, copies of all
periodic and other reports, proxy statements and other materials filed by the
Borrower or any Subsidiary with the Securities and Exchange Commission, or any
Governmental Authority succeeding to any or all of the functions of said
Commission, or with any national securities exchange, or distributed by the
Borrower to its shareholders generally, as the case may be; and

          (e)  promptly following any request therefor, such other information
which the Borrower possesses regarding the operations, business affairs and
financial condition of the Borrower or any Subsidiary, or compliance with the
terms of this Agreement, as the Administrative Agent may reasonably request (in
sufficient copies for the Administrative Agent to deliver to all Lenders).

                                     -32-
<PAGE>

          SECTION 5.02.  Notices of Material Events. The Borrower, promptly
                         --------------------------
after it becomes aware of the following, will furnish to the Administrative
Agent and each Lender written notice of the following:

          (a)  the occurrence of any Default;

          (b)  the filing or commencement of any action, suit or proceeding by
or before any arbitrator or Governmental Authority against or affecting the
Borrower or any Affiliate thereof that, if adversely determined, would
reasonably be expected to result in a Material Adverse Effect;

          (c)  the occurrence of any ERISA Event that, alone or together with
any other ERISA Events that have occurred, would reasonably be expected to
result in a Material Adverse Effect;

          (d)  one or more judgments for the payment of money in an aggregate
amount in excess of $25,000,000 shall be rendered against the Borrower, any
Subsidiary or any combination thereof and the same shall remain undischarged for
a period of 30 consecutive days during which execution shall not be effectively
stayed, or any action shall be legally taken by a judgment creditor to attach or
levy upon any assets of the Borrower or any Subsidiary to enforce any such
judgment; and

          (e)  any other development that results in, or would reasonably be
expected to result in, a Material Adverse Effect.

Each notice delivered under this Section shall be accompanied by a statement of
a Financial Officer or other executive officer of the Borrower setting forth the
details of the event or development requiring such notice and any action taken
or proposed to be taken with respect thereto.

          SECTION 5.03.  Existence; Conduct of Business. The Borrower will, and
                         ------------------------------
will cause each of its Restricted Subsidiaries to, do or cause to be done all
things necessary to preserve, renew and keep in full force and effect its legal
existence and the rights, licenses, permits, privileges and franchises material
to the conduct of its business where the failure to do so would reasonably be
expected to result in a Material Adverse Effect; provided that the foregoing
                                                 --------
shall not prohibit any merger, consolidation, liquidation or dissolution
permitted under Section 6.03.

          SECTION 5.04.  Payment of Obligations. The Borrower will, and will
                         ----------------------
cause each of its Restricted Subsidiaries to, pay its obligations, including Tax
liabilities, that, if not paid, would reasonably be expected to result in a
Material Adverse Effect before the same shall become delinquent or in default,
except where (a) the validity or amount thereof is being contested in good faith
by appropriate proceedings, (b) the Borrower or such Restricted Subsidiary has
set aside on its books adequate reserves with respect thereto in accordance with
GAAP and (c) the failure to make payment pending such contest would not
reasonably be expected to result in a Material Adverse Effect.

          SECTION 5.05.  Maintenance of Properties; Insurance. The Borrower
                         ------------------------------------
will, and will cause each of its Restricted Subsidiaries to, (a) keep and
maintain all property material to the conduct of its business in good working
order and condition, ordinary wear and tear excepted, and (b) maintain, with
financially sound and reputable insurance companies, insurance in such amounts
(with no greater risk retention) and against such risks as are customarily
maintained by companies of established repute engaged in the same or similar
businesses operating in the same or similar locations.

                                     -33-
<PAGE>

          SECTION 5.06.  Books and Records; Inspection Rights. The Borrower
                         ------------------------------------
will, and will cause each of its Restricted Subsidiaries to, keep proper books
of record and account in which full, true and correct entries are made of all
dealings and transactions in relation to its business and activities. The
Borrower will, and will cause each of its Restricted Subsidiaries to, permit any
representatives designated by the Administrative Agent or any Lender, upon
reasonable prior notice, to visit and inspect its properties, and to discuss its
affairs, finances and condition with its officers during normal business hours;
provided however, that the Borrower may coordinate such visits and inspection at
-------- -------
reasonable times and interval to include more than one Lender if more than one
Lender requests such visits and inspections.

          SECTION 5.07.  Compliance with Laws, Material Contractual Obligations.
                         -------------------------------------------------------
The Borrower will, and will cause each of its Restricted Subsidiaries to, comply
with all laws, rules, regulations and orders of any Governmental Authority
applicable to it or its property, and all indentures, agreements and other
instruments binding upon it or its property, where the failure to do so,
individually or in the aggregate, would reasonably be expected to result in a
Material Adverse Effect.

          SECTION 5.08.  Use of Proceeds. The proceeds of the Loans will be
                         ---------------
used only for (a) the payment in full of the Existing Titan Credit Facility, to
the extent not paid in full using the proceeds of loans made under the 5-Year
Revolving Credit Facility, (b) for working capital and (c) general corporate
purposes. No part of the proceeds of any Loan will be used, whether directly or
indirectly, for any purpose that entails a violation of any of the Regulations
of the Board, including Regulations U and X.

          SECTION 5.09.  Additional Subsidiaries. If any additional Subsidiary
                         -----------------------
is formed or acquired after the Effective Date, the Borrower will notify the
Administrative Agent and the Lenders thereof and, if such Subsidiary will be a
Restricted Subsidiary, the Borrower will cause such Subsidiary to execute a
Subsidiary Guaranty Agreement within three Business Days after such Subsidiary
is formed or acquired.

          SECTION 5.10.  Environmental Matters. The Borrower has established
                         ---------------------
and implemented, or will establish and implement, and will cause each of its
Restricted Subsidiaries to establish and implement, such procedures as may be
necessary to continuously determine and assure that any failure of the following
does not have a Material Adverse Effect: (i) all property of the Borrower and
its Restricted Subsidiaries and the operations conducted thereon are in
compliance with and do not violate the requirements of any Environmental Laws,
(ii) no oil or solid wastes are disposed of or otherwise released on or to any
property owned by the Borrower or its Restricted Subsidiaries except in
compliance with Environmental Laws, (iii) no hazardous substance will be
released on or to any such property in a quantity equal to or exceeding that
quantity which requires reporting pursuant to Section 103 of CERCLA, and (iv) no
oil or hazardous substance is released on or to any such property so as to pose
an imminent and substantial endangerment to public health or welfare or the
environment.


                                  ARTICLE VI

                              Negative Covenants
                              ------------------

          Until the Commitments have expired or terminated and the principal of
and interest on each Loan and all fees payable hereunder have been paid in full,
the Borrower covenants and agrees with the Lenders that:

          SECTION 6.01.  Indebtedness. The Borrower will not (i) incur or
                         ------------
assume any Funded Indebtedness either secured by Liens on any property of the
Borrower or consisting of Capital Lease

                                     -34-
<PAGE>

Obligations nor (ii) permit any Restricted Subsidiary to incur or assume any
Funded Indebtedness (whether or not secured by any Liens on any assets of the
Restricted Subsidiary), in an aggregate principal amount in respect to the
Funded Indebtedness under clauses (i) and (ii) (but without duplication)
exceeding $35,000,000 at any one time outstanding. The foregoing limitation
shall exclude and not limit the following:

          (a)  Funded Indebtedness created under the Loan Documents;

          (b)  Funded Indebtedness existing on the date hereof and set forth on
Schedule 6.01 and extensions, renewals and replacements of any such Funded
Indebtedness that do not increase the outstanding principal amounts thereof;

          (c)  Funded Indebtedness of any Restricted Subsidiary owing to the
Borrower or to another Restricted Subsidiary;

          (d)  Guaranties by any Restricted Subsidiary of Funded Indebtedness of
the Borrower which is not prohibited by this Section;

          (e)  Funded Indebtedness of the Borrower secured by Liens permitted
under Section 6.02 (a) through (c);

          (f)  Guarantees in respect of Funded Indebtedness permitted under
Section 6.04; and

          (g)  Funded Indebtedness of the Borrower under the 5-Year Revolving
Credit Facility.

For purposes hereof, the amount of any such Funded Indebtedness shall be deemed
to be, in the case of clause (i), the lesser of the liability of Borrower in
respect of such Funded Indebtedness or the book value of the property securing
such Funded Indebtedness and, in the case of clause (ii), the liability of the
Restricted Subsidiary in respect of such Funded Indebtedness.

          SECTION 6.02.  Liens. The Borrower will not, and will not permit any
                         -----
Restricted Subsidiary to, create, incur, assume or permit to exist any Lien on
any property or asset now owned or hereafter acquired by it, except:

          (a)  Permitted Encumbrances;

          (b)  any Lien on any property or asset of the Borrower or any
Restricted Subsidiary existing on the date hereof and set forth in Schedule
6.02; provided that (i) such Lien shall not apply to any other property or asset
      --------
of the Borrower or any Restricted Subsidiary and (ii) such Lien shall secure
only those obligations which it secures on the date hereof and extensions,
renewals and replacements thereof that do not increase the outstanding principal
amount thereof;

          (c)  any Lien existing on any property or asset prior to the
acquisition thereof by the Borrower or any Restricted Subsidiary or existing on
any property or asset of any Person that becomes a Restricted Subsidiary after
the date hereof prior to the time such Person becomes a Restricted Subsidiary;
provided that (i) such Lien is not created in contemplation of or in connection
--------
with such acquisition or such Person becoming a Restricted Subsidiary, as the
case may be, (ii) such Lien shall not apply to any other property or assets of
the Borrower or any Restricted Subsidiary and (iii) such Lien shall secure only
those obligations which it secures on the date of such acquisition or the date
such Person becomes a Restricted

                                     -35-
<PAGE>

Subsidiary, as the case may be and extensions, renewals and replacements thereof
that do not increase the outstanding principal amount thereof;

          (d)  Liens on fixed or capital assets acquired, constructed or
improved by the Borrower or any Restricted Subsidiary; provided that (i) such
                                                       --------
security interests secure Indebtedness permitted under Section 6.01, (ii) such
security interests and the Indebtedness secured thereby are incurred prior to or
within 90 days after such acquisition or the completion of such construction or
improvement, (iii) the Indebtedness secured thereby does not exceed the cost of
acquiring, constructing or improving such fixed or capital assets and (iv) such
security interests shall not apply to any other property or assets of the
Borrower or any Restricted Subsidiary; and

          (e)  Liens securing Indebtedness permitted by Section 6.01.

          SECTION 6.03.  Fundamental Changes. The Borrower will not, and will
                         -------------------
not permit any Restricted Subsidiary to, merge into or consolidate with any
other Person, or permit any other Person to merge into or consolidate with it,
or sell, transfer, lease or otherwise dispose of (in one transaction or in a
series of transactions) all or any substantial part of its assets, or all or
substantially all of the stock of any of its Subsidiaries (in each case, whether
now owned or hereafter acquired), or liquidate or dissolve, except that, if at
the time thereof and immediately after giving effect thereto no Default shall
have occurred and be continuing (i) any Subsidiary may merge into the Borrower
in a transaction in which the Borrower is the surviving corporation, (ii) any
Subsidiary may merge into any Restricted Subsidiary in a transaction in which
the surviving entity is a Restricted Subsidiary; provided that any such merger
                                                 --------
involving a Person that is not a wholly owned Subsidiary immediately prior to
such merger shall not be permitted unless also permitted by Section 6.06, (iii)
any Subsidiary may sell, transfer, lease or otherwise dispose of its assets to
the Borrower or to another Restricted Subsidiary, (iv) any Subsidiary may
liquidate or dissolve if the Borrower determines in good faith that such
liquidation or dissolution is in the best interests of the Borrower and is not
materially disadvantageous to the Lenders and (v) any Restricted Subsidiary may
merge or may sell, transfer, lease or otherwise dispose of its assets in a
transaction in which a Restricted Subsidiary is not the surviving entity or the
transferee provided that such transaction is permitted under Section 6.06 or
Section 6.10.

Borrower will not, and will not permit any of its Restricted Subsidiaries to,
permit any material change in the character of the business of the Borrower and
the Restricted Subsidiaries taken as a whole, as carried on at the date hereof,
except as may be permitted pursuant to this Agreement.

          SECTION 6.04.  Guarantees. Borrower will not, and will not permit any
                         ----------
Restricted Subsidiary to, create, incur, assume or permit to exist liability in
respect on a Guarantee of Indebtedness of a Person other than of Borrower or a
Restricted Subsidiary where such liability under all such Guarantees exceeds
$25,000,000 in the aggregate at any one time.

          SECTION 6.05.  Hedging Agreements. The Borrower will not, and will
                         ------------------
not permit any of its Restricted Subsidiaries to, enter into any Hedging
Agreement, other than Hedging Agreements entered into in the ordinary course of
business to hedge or mitigate risks to which the Borrower or any Restricted
Subsidiary is exposed in the conduct of its business or the management of its
liabilities; provided, however, the Borrower will not and will not permit any
             --------  -------
Restricted Subsidiary to enter into any Hedging Agreement with respect to
Hydrocarbons at any one time outstanding for amounts in the aggregate in excess
of 85% of all gas production and 85% of all oil production from Borrower's
consolidated proved producing properties.

                                     -36-
<PAGE>

          SECTION 6.06.  Restricted Payments. (a) The Borrower will not, and
                         -------------------
will not permit any of its Restricted Subsidiaries to, declare or make, or agree
to pay or make, directly or indirectly, any Restricted Payment, except (i) the
Borrower may declare and pay dividends with respect to its capital stock not to
exceed $10,000,000 in the aggregate in any fiscal year, (ii) Restricted
Subsidiaries may declare and pay dividends ratably with respect to their capital
stock, (iii) the Borrower may make Restricted Payments pursuant to and in
accordance with stock option plans or other benefit plans for management or
employees of the Borrower and its Subsidiaries, (iv) Borrower or any Restricted
Subsidiary may make Restricted Payments in respect of Employment Arrangements
(including but not limited to purchase of Equity Interests in Borrower), (v)
Borrower or any Restricted Subsidiary may make a Restricted Payment pursuant to
a Put Arrangement, (vi) Borrower or any Restricted Subsidiary may make dividends
or distributions of common Equity Interests or options or rights to acquire
common Equity Interests, and (vii) Borrower or any Restricted Subsidiary may
make other Restricted Payments (other than cash dividends on its common Stock)
provided that immediately after giving effect to such Restricted Payments under
this clause (vii), the aggregate amount of Restricted Payments made under this
clause (vii) after September 30, 2000 does not exceed the sum of (A) $60,000,000
plus (B) 50% of Borrower's consolidated quarterly net income (if positive) for
each calendar quarter ended during the applicable Calculation Period, plus (C)
all interest and principal payments, dividends, distributions and other proceeds
received by Borrower or any Restricted Subsidiary in respect of any Restricted
Investment during the applicable Calculation Period, plus (D) all Restricted
Investments in any Unrestricted Subsidiary which is redesignated as a Restricted
Subsidiary. As used above, the applicable "Calculation Period" with respect to a
Restricted Payment means the period (taken as one accounting period) from and
after June 30, 2000 to and including the last day of the fiscal quarter ended
immediately preceding the date of such Restricted Payment.

          (b)  The Borrower will maintain and evidence to the Administrative
Agent a commitment for funding the amount of any Put Arrangement Liability,
which may include, but is not limited to, availability under this Agreement or
under the 5-Year Revolving Credit Facility.

          SECTION 6.07.  Transactions with Affiliates. The Borrower will not,
                         ----------------------------
and will not permit any of its Restricted Subsidiaries to, sell, lease or
otherwise transfer any property or assets to, or purchase, lease or otherwise
acquire any property or assets from, or otherwise engage in any other
transactions which involve an outflow of money or other property from the
Borrower or its Restricted Subsidiaries to an Affiliate of the Borrower or its
Restricted Subsidiaries with, any of its Affiliates, except (a) at prices and on
terms and conditions within such transaction taken as a whole that are not
materially less favorable to the Borrower or such Restricted Subsidiary than
could be obtained on an arm's-length basis from unrelated third parties, (b)
transactions between or among the Borrower and its Restricted Subsidiaries not
involving any other Affiliate and (c) any Restricted Payment permitted by
Section 6.06. Notwithstanding the foregoing, the restrictions set forth in this
Section shall not apply to the payment of reasonable and customary fees to
directors who are not employees of the Borrower or the payment of reasonable
financial advisory and similar fees to equity investors in the Borrower or its
Subsidiaries who are not employees.

          SECTION 6.08.  Restrictive Agreements. The Borrower will not, and
                         ----------------------
will not permit any of its Restricted Subsidiaries to, directly or indirectly,
enter into, incur or permit to exist any agreement or other arrangement that
prohibits, restricts or imposes any condition upon the ability of any Restricted
Subsidiary to pay dividends or other distributions with respect to any shares of
its capital stock or to make or repay loans or advances to the Borrower or any
other Restricted Subsidiary or to Guarantee Indebtedness of the Borrower or any
other Restricted Subsidiary; provided that (i) the foregoing shall not apply to
                             --------
restrictions and conditions imposed by laws, regulations or orders of any
Governmental Authority or by this Agreement, (ii) the foregoing shall not apply
to restrictions and conditions existing on the date hereof identified on
Schedule 6.08 (but shall apply to any extension or renewal of, or any amendment
or

                                     -37-
<PAGE>

modification expanding the scope of, any such restriction or condition), (iii)
the foregoing shall not apply to customary restrictions and conditions contained
in agreements relating to the sale of a Subsidiary pending such sale, provided
such restrictions and conditions apply only to the Subsidiary that is to be sold
and such sale is permitted hereunder, and (iv) the foregoing shall not prohibit
provisions in indentures which relate to Subsidiary Guarantees which do not
prohibit Guarantees contemplated by this Agreement.

          SECTION 6.09.  Change in Fiscal Year. The Borrower will not change
                         ---------------------
the manner in which either the last day of its fiscal year or the last days of
the first three fiscal quarters of its fiscal year is calculated.

          SECTION 6.10.  Asset Sales.  The Borrower will not, and will not
                         -----------
permit any of the Restricted Subsidiaries to, sell, transfer, lease or otherwise
dispose of any asset, including any Equity Interest in a Restricted Subsidiary
owned by it, nor will the Borrower permit any of Restricted Subsidiaries to
issue any additional Equity Interest in such Restricted Subsidiary, except:

          (a)  sales of inventory, used or surplus equipment and Permitted
Investments in the ordinary course of business;

          (b)  sales, transfers and dispositions by a Subsidiary to the Borrower
or another Restricted Subsidiary;

          (c)  sales of Oil and Gas Properties which have no volumes classified
as proved reserves on the most recent Reserve Report;

          (d)  sales of Oil and Gas Properties or Equity Interests in a
Restricted Subsidiary whose assets consist, in all material respects, of Oil and
Gas Properties which have volumes classified as proved reserves on the most
recent Reserve Report not to exceed:

               (i)  in fiscal year ending December 31, 2000, proved reserves
     having a fair market value of $50,000,000; and

               (ii) in fiscal year 2001 and each fiscal year thereafter, 10% of
     the previous year's SEC PV-10 for proved reserves; and

          (e)  other sales, transfers and dispositions not to exceed $10,000,000
in the aggregate in any fiscal year.

          SECTION 6.11.  Sale and Leaseback Transactions. The Borrower will
                         -------------------------------
not, and will not permit any of the Subsidiaries to, enter into any arrangement,
directly or indirectly, whereby it shall sell or transfer any property, real or
personal, used or useful in its business, whether now owned or hereinafter
acquired, and thereafter rent or lease such property or other property that it
intends to use for substantially the same purpose or purposes as the property
sold or transferred, except for any such sale of any fixed or capital assets
that is made for cash consideration in an amount not less than the cost of such
fixed or capital asset and is consummated within 90 days after the Borrower or
such Subsidiary acquires or completes the construction of such fixed or capital
asset; provided that the aggregate costs of any sales permitted by this Section
       --------
shall not exceed $25,000,000.

          Section 6.12.  "Margin Calls" on Hedging Agreements. With respect to
                          -----------------------------------
Hedging Agreements, neither the Borrower nor any Subsidiary shall post cash or
any other collateral or credit support

                                     -38-
<PAGE>

whatsoever (other than letters of credit) in response to a call on Borrower or
any Subsidiary for credit support or eligible collateral in an aggregate amount
greater than $20,000,000 for all Hedging Agreements.

          SECTION 6.13.  Designation of Restricted Subsidiaries.  Borrower shall
                         --------------------------------------
not designate a Restricted Subsidiary as an Unrestricted Subsidiary or an
Unrestricted Subsidiary as a Restricted Subsidiary if a Default has occurred
which is continuing or if, after giving effect thereto, a Default shall exist or
shall result from such designation.


                                  ARTICLE VII

                              Financial Covenants
                              -------------------

     Until the Commitments have expired or terminated and the principal of and
interest on each Loan and all fees payable hereunder have been paid in full and
all other Obligations satisfied in full, the Borrower covenants and agrees with
the Lenders that:

          SECTION 7.01.  Adjusted Consolidated Net Worth.  The Borrower will at
                         -------------------------------
all times maintain Adjusted Consolidated Net Worth (as defined below) in an
amount not less than $300,000,000.  As used in this Agreement, "Adjusted
Consolidated Net Worth" means, at any particular time, all amounts which, in
conformity with GAAP, would be included as stockholders' equity on a
consolidated balance sheet of the Borrower, adjusted to exclude (a) the effects
of common stock of the Borrower being repurchased or being subject to repurchase
under employment arrangements accounted for as variable plans under APB Opinion
No. 25 (provided that any new arrangements entered into after the Effective Date
as well as any amendments to arrangements existing on the Effective Date, shall
not be excluded from consideration to the extent that such arrangements
materially increase the Borrower's obligations), and (b) the after tax effects
of the following post-Effective Date events (i) write-downs after June 30, 2000
under FASB Statement No. 19, (ii) non-cash write-ups or write-downs of assets
after June 30, 2000 under FASB Statement No. 121, (iii) non-cash gains, losses
or adjustments under FASB Statement No. 133, (iv) non-cash charges to earnings
for options or stock issued and accounted for under APB Opinion No.  25 or FASB
Statement 123, and (v) post-Effective Date changes in GAAP.

          SECTION 7.02.  Debt Coverage Ratios.  The Borrower shall not at any
                         --------------------
time permit the ratio of  Funded Indebtedness as of such date to cumulative
EBITDAX for the four (4) fiscal quarters most recently ended for which Borrower
has delivered financial statements pursuant to Section 5.01(a) or (b) to exceed
4.0 to 1.0.

                                  ARTICLE VIII

                               Events of Default
                               -----------------

          If any of the following events ("Events of Default") shall occur:
                                           -----------------

          (a) the Borrower shall fail to pay any principal of any Loan when and
as the same shall become due and payable, whether at the due date thereof or at
a date fixed for prepayment thereof or otherwise;

          (b)  the Borrower shall fail to pay any interest on any Loan or any
fee or any other amount (other than an amount referred to in clause (a) of this
Article) payable under this Agreement, when and as

                                     -39-
<PAGE>

the same shall become due and payable, and such failure shall continue
unremedied for a period of three Business Days;

          (c)  any representation or warranty made or deemed made by or on
behalf of the Borrower or any Subsidiary in or in connection with this Agreement
or any amendment or modification hereof or waiver hereunder, or in any report,
certificate, financial statement or other document furnished pursuant to or in
connection with this Agreement or any amendment or modification hereof or waiver
hereunder, shall prove to have been incorrect in any material respect when made
or deemed made;

          (d)  the Borrower shall fail to observe or perform any covenant,
condition or agreement contained in Sections 5.02, 5.03 (with respect to the
Borrower's existence) or 5.08 or in Article VI;

          (e)  the Borrower shall fail to observe or perform any covenant,
condition or agreement contained in this Agreement (other than those specified
in clause (a), (b) or (d) of this Article), and such failure shall continue
unremedied for a period of 30 days after notice thereof from the Administrative
Agent to the Borrower (which notice will be given at the request of the Required
Lender);

          (f)  the Borrower or any Restricted Subsidiary shall fail to make any
payment (whether of principal or interest and regardless of amount) in respect
of any Material Indebtedness, when and as the same shall become due and payable
(other than a payment which is contested in good faith by appropriate
proceeding) and such failure shall continue unremedied for a period of three
Business Days;

          (g)  any event or condition occurs that results in any Material
Indebtedness becoming due prior to its scheduled maturity or that enables or
permits the holder or holders of any Material Indebtedness or any trustee or
agent on its or their behalf to cause any Material Indebtedness to become due,
or to require the prepayment, repurchase, redemption or defeasance thereof,
prior to its scheduled maturity and such event or condition shall continue
unremedied beyond any applicable period of grace;

          (h)  an involuntary proceeding shall be commenced or an involuntary
petition shall be filed seeking (i) liquidation, reorganization or other relief
in respect of the Borrower or any Material Subsidiary or its debts, or of a
substantial part of its assets, under any  Federal, state or foreign bankruptcy,
insolvency, receivership or similar law now or hereafter in effect or (ii) the
appointment of a receiver, trustee, custodian, sequestrator, conservator or
similar official for the Borrower or any Material Subsidiary or for a
substantial part of its assets, and, in any such case, such proceeding or
petition shall continue undismissed for 60 days or an order or decree approving
or ordering any of the foregoing shall be entered;

          (i)  the Borrower or any Material Subsidiary shall (i) voluntarily
commence any proceeding or file any petition seeking liquidation, reorganization
or other relief under any Federal, state or foreign bankruptcy, insolvency,
receivership or similar law now or hereafter in effect, (ii) consent to the
institution of, or fail to contest in a timely and appropriate manner, any
proceeding or petition described in clause (h) of this Article, (iii) apply for
or consent to the appointment of a receiver, trustee, custodian, sequestrator,
conservator or similar official for the Borrower or any Material Subsidiary or
for a substantial part of its assets, (iv) file an answer admitting the material
allegations of a petition filed against it in any such proceeding, (v) make a
general assignment for the benefit of creditors or (vi) take any action for the
purpose of effecting any of the foregoing;

          (j)  the Borrower or any Material Subsidiary shall become unable,
admit in writing its inability or fail generally to pay its debts as they become
due;

                                     -40-
<PAGE>

          (k)  one or more judgments for the payment of money in an aggregate
amount in excess of $25,000,000 shall be rendered against the Borrower, any
Restricted Subsidiary or any combination thereof and the same shall remain
undischarged for a period of 30 consecutive days during which execution shall
not be effectively stayed, or any action shall be legally taken by a judgment
creditor to attach or levy upon any assets of the Borrower or any Restricted
Subsidiary to enforce any such judgment;

          (l)  an ERISA Event shall have occurred that, when taken together with
all other ERISA Events that have occurred, results in a Material Adverse Effect;

          (m)  a Change in Control shall occur; or

          (n)  an "Event of Default" shall occur under the 5-Year Credit
     Agreement;

then, and in every such event (other than an event with respect to the Borrower
described in clause (h) or (i) of this Article), and at any time thereafter
during the continuance of such event, the Administrative Agent may, and at the
request of the Required Lenders shall, by notice to the Borrower, take either or
both of the following actions, at the same or different times: (i) terminate the
Commitments, and thereupon the Commitments shall terminate immediately, and (ii)
declare the Loans then outstanding to be due and payable in whole (or in part,
in which case any principal not so declared to be due and payable may thereafter
be declared to be due and payable), and thereupon the principal of the Loans so
declared to be due and payable, together with accrued interest thereon and all
fees and other obligations of the Borrower accrued hereunder, shall become due
and payable immediately, without presentment, demand, protest or other notice of
any kind, all of which are hereby waived by the Borrower; and in case of any
event with respect to the Borrower described in clause (h) or (i) of this
Article, the Commitments shall automatically terminate and the principal of the
Loans then outstanding, together with accrued interest thereon and all fees and
other obligations of the Borrower accrued hereunder, shall automatically become
due and payable, without presentment, demand, protest or other notice of any
kind, all of which are hereby waived by the Borrower.


                                   ARTICLE IX

                            The Administrative Agent
                            ------------------------

          Each of the Lenders hereby irrevocably appoints the Administrative
Agent as its agent and authorizes the Administrative Agent to take such actions
on its behalf and to exercise such powers as are delegated to the Administrative
Agent by the terms hereof, together with such actions and powers as are
reasonably incidental thereto.

          The bank serving as the Administrative Agent hereunder shall have the
same rights and powers in its capacity as a Lender as any other Lender and may
exercise the same as though it were not the Administrative Agent, and such bank
and its Affiliates may accept deposits from, lend money to and generally engage
in any kind of business with the Borrower or any Subsidiary or other Affiliate
thereof as if it were not the Administrative Agent hereunder.

          The Administrative Agent shall not have any duties or obligations
except those expressly set forth herein.  Without limiting the generality of the
foregoing, (a) the Administrative Agent shall not be subject to any fiduciary or
other implied duties, regardless of whether a Default has occurred and is
continuing, (b) the Administrative Agent shall not have any duty to take any
discretionary action or exercise any discretionary powers, except discretionary
rights and powers expressly contemplated hereby that the

                                     -41-
<PAGE>

Administrative Agent is required to exercise in writing by the Required Lenders
(or such other number or percentage of the Lenders as shall be necessary under
the circumstances as provided in Section 10.02), and (c) except as expressly set
forth herein, the Administrative Agent shall not have any duty to disclose, and
shall not be liable for the failure to disclose, any information relating to the
Borrower or any of its Subsidiaries that is communicated to or obtained by the
bank serving as Administrative Agent or any of its Affiliates in any capacity.
The Administrative Agent shall not be liable for any action taken or not taken
by it with the consent or at the request of the Required Lenders (or such other
number or percentage of the Lenders as shall be necessary under the
circumstances as provided in Section 10.02) or in the absence of its own gross
negligence or wilful misconduct. The Administrative Agent shall be deemed not to
have knowledge of any Default unless and until written notice thereof is given
to the Administrative Agent by the Borrower or a Lender, and the Administrative
Agent shall not be responsible for or have any duty to ascertain or inquire into
(i) any statement, warranty or representation made in or in connection with this
Agreement, (ii) the contents of any certificate, report or other document
delivered hereunder or in connection herewith, (iii) the performance or
observance of any of the covenants, agreements or other terms or conditions set
forth herein, (iv) the validity, enforceability, effectiveness or genuineness of
this Agreement or any other agreement, instrument or document, or (v) the
satisfaction of any condition set forth in Article IV or elsewhere herein, other
than to confirm receipt of items expressly required to be delivered to the
Administrative Agent.

          The Administrative Agent shall be entitled to rely upon, and shall not
incur any liability for relying upon, any notice, request, certificate, consent,
statement, instrument, document or other writing believed by it to be genuine
and to have been signed or sent by the proper Person. The Administrative Agent
also may rely upon any statement made to it orally or by telephone and believed
by it to be made by the proper Person, and shall not incur any liability for
relying thereon. The Administrative Agent may consult with legal counsel (who
may be counsel for the Borrower), independent accountants and other experts
selected by it, and shall not be liable for any action taken or not taken by it
in accordance with the advice of any such counsel, accountants or experts.

          The Administrative Agent may perform any and all its duties and
exercise its rights and powers by or through any one or more sub-agents
appointed by the Administrative Agent. The Administrative Agent and any such
sub-agent may perform any and all its duties and exercise its rights and powers
through their respective Related Parties. The exculpatory provisions of the
preceding paragraphs shall apply to any such sub-agent and to the Related
Parties of the Administrative Agent and any such sub-agent, and shall apply to
their respective activities in connection with the syndication of the credit
facilities provided for herein as well as activities as Administrative Agent.

          Subject to the appointment and acceptance of a successor
Administrative Agent as provided in this paragraph, the Administrative Agent may
resign at any time by notifying the Lenders and the Borrower.  Upon any such
resignation, the Required Lenders shall have the right, in consultation with the
Borrower, to appoint a successor.  If  no successor shall have been so appointed
by the Required Lenders and shall have accepted such appointment within 30 days
after the retiring Administrative Agent gives notice of its resignation, then
the retiring Administrative Agent may, on behalf of the Lenders and with the
approval of the Borrower, appoint a successor Administrative Agent; provided,
however Borrower's approval shall not be required if an Event of Default shall
have occurred and be continuing.  Upon the acceptance of its appointment as
Administrative Agent hereunder by a successor, such successor shall succeed to
and become vested with all the rights, powers, privileges and duties of the
retiring Administrative Agent, and the retiring Administrative Agent shall be
discharged from its duties and obligations hereunder.  The fees payable by the
Borrower to a successor Administrative Agent shall be the same as those payable
to its predecessor unless otherwise agreed between the Borrower and such
successor.  After the Administrative Agent's

                                     -42-
<PAGE>

resignation hereunder, the provisions of this Article and Section 10.03 shall
continue in effect for the benefit of such retiring Administrative Agent, its
sub-agents and their respective Related Parties in respect of any actions taken
or omitted to be taken by any of them while it was acting as Administrative
Agent.

          Each Lender acknowledges that it has, independently and without
reliance upon the Administrative Agent or any other Lender and based on such
documents and information as it has deemed appropriate, made its own credit
analysis and decision to enter into this Agreement. Each Lender also
acknowledges that it will, independently and without reliance upon the
Administrative Agent or any other Lender and based on such documents and
information as it shall from time to time deem appropriate, continue to make its
own decisions in taking or not taking action under or based upon this Agreement,
any related agreement or any document furnished hereunder or thereunder.


                                   ARTICLE X

                                 Miscellaneous
                                 -------------

          SECTION 10.01.  Notices.  Except in the case of notices and other
                          -------
communications expressly permitted to be given by telephone and except for
financial statements and notices to be delivered pursuant to Section 5.01 or
5.02 which may be delivered electronically, all notices and other communications
provided for herein shall be in writing and shall be delivered by hand or
overnight courier service, mailed by certified or registered mail or sent by
telecopy, as follows:

          (a)  if to the Borrower, to it at 500 West Illinois, Midland, Texas
79701, Attention of John L. Benfatti (Telecopy No. (915) 687-4023);

          (b)  if to the Administrative Agent, to The Chase Manhattan Bank, Loan
and Agency Services Group, One Chase Manhattan Plaza, 8th Floor, New York, New
York 10081, Attention of Muniram Appanna (Telecopy No. (212) 552-2261), with a
copy to The Chase Manhattan Bank, 600 Travis, 20/th/ Floor, Houston, Texas
77002, Attention of Peter M. Licalzi  (Telecopy No. (713) 216-4117); and

          (c)  if to any other Lender, to it at its address (or telecopy number)
set forth under such Lender's name on its signature page hereto.

Any party hereto may change its address or telecopy number for notices and other
communications hereunder by notice to the other parties hereto.  All notices and
other communications given to any party hereto in accordance with the provisions
of this Agreement shall be deemed to have been given on the date of receipt.

          SECTION 10.02.  Waivers; Amendments.  (a)  No failure or delay by the
                          -------------------
Administrative Agent or any Lender in exercising any right or power hereunder
shall operate as a waiver thereof, nor shall any single or partial exercise of
any such right or power, or any abandonment or discontinuance of steps to
enforce such a right or power, preclude any other or further exercise thereof or
the exercise of any other right or power.  The rights and remedies of the
Administrative Agent and the Lenders hereunder are cumulative and are not
exclusive of any rights or remedies that they would otherwise have.  No waiver
of any provision of this Agreement or consent to any departure by the Borrower
therefrom shall in any event be effective unless the same shall be permitted by
paragraph (b) of this Section, and then such waiver or consent shall be
effective only in the specific instance and for the purpose for which given.
Without limiting the generality of the foregoing, the making of a Loan shall not
be construed as a waiver of any Default, regardless of

                                     -43-
<PAGE>

whether the Administrative Agent or any Lender may have had notice or knowledge
of such Default at the time.

          (b)  Neither this Agreement nor any provision hereof may be waived,
amended or modified except pursuant to an agreement or agreements in writing
entered into by the Borrower and the Required Lenders or by the Borrower and the
Administrative Agent with the consent of the Required Lenders; provided that no
                                                               --------
such agreement shall (i) increase  the Commitment of any Lender without the
written consent of such Lender, (ii) reduce the principal amount of any Loan or
reduce the rate of interest thereon, or reduce any fees payable hereunder,
without the written consent of each Lender affected thereby, (iii) postpone the
scheduled date of payment of the principal amount of any Loan, or any interest
thereon, or any fees payable hereunder, or reduce the amount of, waive or excuse
any such payment, or postpone the scheduled date of expiration of any
Commitment, without the written consent of each Lender affected thereby, (iv)
change Sections 2.19 and 2.21 in a manner that would alter the pro rata sharing
of payments required thereby, without the written consent of each Lender, or (v)
change any of the provisions of this Section or the definition of "Required
Lenders" or any other provision hereof specifying the number or percentage of
Lenders required to waive, amend or modify any rights hereunder or make any
determination or grant any consent hereunder, without the  written consent of
each Lender.

          SECTION 10.03.  Expenses; Indemnity; Damage Waiver.  (a)  The Borrower
                          ----------------------------------
shall pay (i) all reasonable out-of-pocket expenses incurred by the
Administrative Agent and its Affiliates, including the reasonable fees, charges
and disbursements of counsel for the Administrative Agent, in connection with
the syndication of the credit facilities provided for herein, the preparation
and administration of this Agreement or any amendments, modifications or waivers
of the provisions hereof (whether or not the transactions contemplated hereby or
thereby shall be consummated), and (ii) all out-of-pocket expenses incurred by
the Administrative Agent and each Lender, including the reasonable fees, charges
and disbursements of any counsel for the Administrative Agent, in connection
with the enforcement or protection of its rights in connection with this
Agreement, including its rights under this Section, or in connection with the
Loans made, including all such reasonable out-of-pocket expenses incurred during
any workout, restructuring or negotiations in respect of such Loans.

          (B)  THE BORROWER AGREES TO INDEMNIFY THE ADMINISTRATIVE AGENT AND
EACH LENDER, AND EACH RELATED PARTY OF ANY OF THE FOREGOING PERSONS (EACH SUCH
PERSON BEING CALLED AN "INDEMNITEE") AGAINST, AND HOLD EACH INDEMNITEE HARMLESS
FROM, ANY AND ALL LOSSES, CLAIMS, DAMAGES, LIABILITIES AND RELATED EXPENSES,
INCLUDING THE REASONABLE FEES, CHARGES AND DISBURSEMENTS OF ANY COUNSEL FOR ANY
INDEMNITEE, INCURRED BY OR ASSERTED AGAINST ANY INDEMNITEE ARISING OUT OF, IN
CONNECTION WITH, OR AS A RESULT OF (I) THE EXECUTION OR DELIVERY OF THIS
AGREEMENT OR ANY AGREEMENT OR INSTRUMENT CONTEMPLATED HEREBY, THE PERFORMANCE BY
THE PARTIES HERETO OF THEIR RESPECTIVE OBLIGATIONS HEREUNDER OR THE CONSUMMATION
OF THE TRANSACTIONS OR ANY OTHER TRANSACTIONS CONTEMPLATED HEREBY, (II) ANY LOAN
OR THE USE OF THE PROCEEDS THEREFROM, (III) ANY ACTUAL OR ALLEGED PRESENCE OR
RELEASE OF HAZARDOUS MATERIALS ON OR FROM ANY PROPERTY OWNED OR OPERATED BY THE
BORROWER OR ANY OF ITS SUBSIDIARIES, OR ANY ENVIRONMENTAL LIABILITY RELATED IN
ANY WAY TO THE BORROWER OR ANY OF ITS SUBSIDIARIES, OR (IV) ANY ACTUAL OR
PROSPECTIVE CLAIM, LITIGATION, INVESTIGATION OR PROCEEDING RELATING TO ANY OF
THE FOREGOING, WHETHER BASED ON CONTRACT, TORT OR ANY OTHER THEORY AND
REGARDLESS OF WHETHER ANY INDEMNITEE IS A PARTY THERETO; PROVIDED THAT SUCH
INDEMNITY SHALL NOT, AS TO ANY INDEMNITEE, BE AVAILABLE TO THE EXTENT THAT SUCH
LOSSES, CLAIMS, DAMAGES, LIABILITIES OR RELATED EXPENSES RESULTED FROM THE GROSS
NEGLIGENCE OR WILFUL MISCONDUCT OF SUCH INDEMNITEE.

                                     -44-
<PAGE>

          (c)  To the extent that the Borrower fails to pay any amount required
to be paid by it to the Administrative Agent or the Lenders under paragraph (a)
or (b) of this Section, each Lender severally agrees to pay to the
Administrative Agent or the Lenders, as the case may be, such Lender's
Applicable Percentage (determined as of the time that the applicable
unreimbursed expense or indemnity payment is sought) of such unpaid amount;
provided that the unreimbursed expense or indemnified loss, claim, damage,
--------
liability or related expense, as the case may be, was incurred by or asserted
against the Administrative Agent or the Lenders in its capacity as such.

          (d)  To the extent permitted by applicable law, the Borrower shall not
assert, and hereby waives, any claim against any Indemnitee, on any theory of
liability, for special, indirect, consequential or punitive damages (as opposed
to direct or actual damages) arising out of, in connection with, or as a result
of, this Agreement or any agreement or instrument contemplated hereby, the
Transactions, any Loan or the use of the proceeds thereof.

          (E)  THE FOREGOING INDEMNITIES SHALL EXTEND TO THE INDEMNITEES
NOTWITHSTANDING THE SOLE OR CONCURRENT NEGLIGENCE OF EVERY KIND OR CHARACTER
WHATSOEVER (OTHER THAN GROSS NEGLIGENCE OR WILLFUL MISCONDUCT), WHETHER ACTIVE
OR PASSIVE, WHETHER AN AFFIRMATIVE ACT OR AN OMISSION, INCLUDING WITHOUT
LIMITATION, ALL TYPES OF NEGLIGENT CONDUCT IDENTIFIED IN THE RESTATEMENT
(SECOND) OF TORTS OF ONE OR MORE OF THE INDEMNITEES OR BY REASON OF STRICT
LIABILITY IMPOSED WITHOUT FAULT ON ANY ONE OR MORE OF THE INDEMNITEES.  TO THE
EXTENT THAT AN INDEMNITEE IS FOUND TO HAVE COMMITTED AN ACT OF GROSS NEGLIGENCE
OR WILLFUL MISCONDUCT, THIS CONTRACTUAL OBLIGATION OF INDEMNIFICATION SHALL
CONTINUE BUT SHALL ONLY EXTEND TO THE PORTION OF THE CLAIM THAT IS DEEMED TO
HAVE OCCURRED BY REASON OF EVENTS OTHER THAN THE GROSS NEGLIGENCE OR WILLFUL
MISCONDUCT OF THE INDEMNITEE.

          (f)  All amounts due under this Section shall be payable not later
than 30 days after written demand therefor.

          SECTION 10.04.  Successors and Assigns.  (a)  The provisions of this
                          ----------------------
Agreement shall be binding upon and inure to the benefit of the parties hereto
and their respective successors and assigns permitted hereby, except that the
Borrower may not assign or otherwise transfer any of its rights or obligations
hereunder without the prior written consent of each Lender (and any attempted
assignment or transfer by the Borrower without such consent shall be null and
void).  Nothing in this Agreement, expressed or implied, shall be construed to
confer upon any Person (other than the parties hereto, their respective
successors and assigns permitted hereby and, to the extent expressly
contemplated hereby, the Related Parties of each of the Administrative Agent and
the Lenders) any legal or equitable right, remedy or claim under or by reason of
this Agreement.

          (b)  Any Lender may assign to one or more assignees all or a portion
of its rights and obligations under this Agreement (including all or a portion
of its Commitment and the Loans at the time owing to it); provided  that (i)
                                                          --------
except in the case of an assignment to a Lender or a Lender Affiliate, each of
the Borrower and the Administrative Agent must give their prior written consent
to such assignment (which consent shall not be unreasonably withheld), (ii)
except in the case of an assignment to a Lender or a Lender Affiliate or an
assignment of the entire remaining amount of the assigning Lender's Commitment,
the amount of the Commitment of the assigning Lender subject to each such
assignment (determined as of the date the Assignment and Acceptance with respect
to such assignment is delivered to the Administrative Agent) shall not be less
than $5,000,000 unless each of the Borrower and the Administrative Agent
otherwise consent,

                                     -45-
<PAGE>

(iii) each partial assignment shall be made as an assignment of a proportionate
part of all the assigning Lender's rights and obligations under this Agreement,
(iv) the parties to each assignment shall execute and deliver to the
Administrative Agent an Assignment and Acceptance, together with a processing
and recordation fee of $3,500, and (v) the assignee, if it shall not be a
Lender, shall deliver to the Administrative Agent an Administrative
Questionnaire; and provided further that any consent of the Borrower otherwise
                   -------- -------
required under this paragraph shall not be required if an Event of Default has
occurred and is continuing. Subject to acceptance and recording thereof pursuant
to paragraph (d) of this Section, from and after the effective date specified in
each Assignment and Acceptance the assignee thereunder shall be a party hereto
and, to the extent of the interest assigned by such Assignment and Acceptance,
have the rights and obligations of a Lender under this Agreement, and the
assigning Lender thereunder shall, to the extent of the interest assigned by
such Assignment and Acceptance, be released from its obligations under this
Agreement (and, in the case of an Assignment and Acceptance covering all of the
assigning Lender's rights and obligations under this Agreement, such Lender
shall cease to be a party hereto but shall continue to be entitled to the
benefits of Section 10.03). Any assignment or transfer by a Lender of rights or
obligations under this Agreement that does not comply with this paragraph shall
be treated for purposes of this Agreement as a sale by such Lender of a
participation in such rights and obligations in accordance with paragraph (e) of
this Section.

          (c)  The Administrative Agent, acting for this purpose as an agent of
the Borrower, shall maintain at one of its offices in The City of New York a
copy of each Assignment and Acceptance delivered to it and a register for the
recordation of the names and addresses of the Lenders, and the Commitment of,
and principal amount of the Loans owing to, each Lender pursuant to the terms
hereof from time to time (the "Register").  The entries in the Register shall be
                               --------
conclusive, and the Borrower, the Administrative Agent and the Lenders may treat
each Person whose name is recorded in the Register pursuant to the terms hereof
as a Lender hereunder for all purposes of this Agreement, notwithstanding notice
to the contrary.  The Register shall be available for inspection by the Borrower
and any Lender, at any reasonable time and from time to time upon reasonable
prior notice.

          (d)  Upon its receipt of a duly completed Assignment and Acceptance
executed by an assigning Lender and an assignee, the assignee's completed
Administrative Questionnaire (unless the assignee shall already be a Lender
hereunder), the processing and recordation fee referred to in paragraph (b) of
this Section and any written consent to such assignment required by paragraph
(b) of this Section, the Administrative Agent shall accept such Assignment and
Acceptance and record the information contained therein in the Register.  No
assignment shall be effective for purposes of this Agreement unless it has been
recorded in the Register as provided in this paragraph.

          (e)  Any Lender may, without the consent of the Borrower or the
Administrative Agent sell participations to one or more banks or other entities
(a "Participant") in all or a portion of such Lender's rights and obligations
    -----------
under this Agreement (including all or a portion of its Commitment and the Loans
owing to it); provided that (i) such Lender's obligations under this Agreement
              --------
shall remain unchanged, (ii) such Lender shall remain solely responsible to the
other parties hereto for the performance of such obligations and (iii) the
Borrower, the Administrative Agent and the other Lenders shall continue to deal
solely and directly with such Lender in connection with such Lender's rights and
obligations under this Agreement.  Any agreement or instrument pursuant to which
a Lender sells such a participation shall provide that such Lender shall retain
the sole right to enforce this Agreement and to approve any amendment,
modification or waiver of any provision of this Agreement.  Subject to paragraph
(f) of this Section, the Borrower agrees that each Participant shall be entitled
to the benefits of Sections 2.14, 2.15, 2.16, 2.18 and 2.20 to the same extent
as if it were a Lender and had acquired its interest by assignment pursuant to
paragraph (b) of this Section.  To the extent permitted by law, each Participant
also shall be entitled to the

                                     -46-
<PAGE>

benefits of Section 10.08 as though it were a Lender, provided such Participant
agrees to be subject to Section 2.19 as though it were a Lender.

          (f)  A Participant shall not be entitled to receive any greater
payment under Section 2.16 or 2.20 than the applicable Lender would have been
entitled to receive with respect to the participation sold to such Participant.
A Participant that is not a corporation organized under the laws of the United
States of America or any state thereof, shall comply with and be subject to the
provisions of Section 2.20(f) as though it were a Lender hereunder.  If such
Participant fails to comply with the provisions of Section 2.20(f), such
Participant shall not be entitled to the benefits of Section 2.20.

          (g)  Any Lender may at any time pledge or assign a security interest
in all or any portion of its rights under this Agreement to secure obligations
of such Lender to a Federal Reserve Bank, and this Section shall not apply to
any such pledge or assignment of a security interest; provided that no such
                                                      --------
pledge or assignment of a security interest shall release a Lender from any of
its obligations hereunder or substitute any such pledgee or assignee for such
Lender as a party hereto.

          SECTION 10.05.  Survival.  All covenants, agreements, representations
                          --------
and warranties made by the Borrower herein and in the certificates or other
instruments delivered in connection with or pursuant to this Agreement shall be
considered to have been relied upon by the other parties hereto and shall
survive the execution and delivery of this Agreement and the making of any Loans
and issuance of any Letters of Credit, regardless of any investigation made by
any such other party or on its behalf and notwithstanding that the
Administrative Agent or any Lender may have had notice or knowledge of any
Default or incorrect representation or warranty at the time any credit is
extended hereunder, and shall continue in full force and effect as long as the
principal of or any accrued interest on any Loan or any fee or any other amount
payable under this Agreement is outstanding and unpaid and so long as the
Commitments have not expired or terminated. The provisions of Sections 2.14,
2.15, 2.16, 2.18 and 2.20 and Article VIII shall survive and remain in full
force and effect regardless of the consummation of the transactions contemplated
hereby, the repayment of the Loans, the expiration or termination of the
Commitments or the termination of this Agreement or any provision hereof.

          SECTION 10.06.  Counterparts; Integration; Effectiveness.  This
                          ----------------------------------------
Agreement may be executed in counterparts (and by different parties hereto on
different counterparts), each of which shall constitute an original, but all of
which when taken together shall constitute a single contract. This Agreement and
any separate letter agreements with respect to fees payable to the
Administrative Agent constitute the entire contract among the parties relating
to the subject matter hereof and supersede any and all previous agreements and
understandings, oral or written, relating to the subject matter hereof. Except
as provided in Section 4.01, this Agreement shall become effective when it shall
have been executed by the Administrative Agent and when the Administrative Agent
shall have received counterparts hereof which, when taken together, bear the
signatures of each of the other parties hereto, and thereafter shall be binding
upon and inure to the benefit of the parties hereto and their respective
successors and assigns. Delivery of an executed counterpart of a signature page
of this Agreement by telecopy shall be effective as delivery of a manually
executed counterpart of this Agreement.

          SECTION 10.07.  Severability.  Any provision of this Agreement held to
                          ------------
be invalid, illegal or unenforceable in any jurisdiction shall, as to such
jurisdiction, be ineffective to the extent of such invalidity, illegality or
unenforceability without affecting the validity, legality and enforceability of
the remaining provisions hereof; and the invalidity of a particular provision in
a particular jurisdiction shall not invalidate such provision in any other
jurisdiction.

                                     -47-
<PAGE>

          SECTION 10.08.  Right of Setoff.  If an Event of Default shall have
                          ---------------
occurred and be continuing, each Lender and each of its Affiliates is hereby
authorized at any time and from time to time, to the fullest extent permitted by
law, to set off and apply any and all deposits (general or special, time or
demand, provisional or final) at any time held and other obligations at any time
owing by such Lender or Affiliate to or for the credit or the account of the
Borrower against any of and all the obligations of the Borrower now or hereafter
existing under this Agreement held by such Lender, irrespective of whether or
not such Lender shall have made any demand under this Agreement and although
such obligations may be unmatured. The rights of each Lender under this Section
are in addition to other rights and remedies (including other rights of setoff)
which such Lender may have.

          SECTION 10.09.  Governing Law; Jurisdiction; Consent to Service of
                          --------------------------------------------------
Process. (a) This Agreement shall be construed in accordance with and governed
-------
by the law of the State of Texas.

          (b)  The Borrower hereby irrevocably and unconditionally submits, for
itself and its property, to the nonexclusive jurisdiction of the courts of the
State of Texas or of the United States of America for the Southern District of
Texas, and any appellate court from any thereof, in any action or proceeding
arising out of or relating to this Agreement, or for recognition or enforcement
of any judgment, and each of the parties hereto hereby irrevocably and
unconditionally agrees that all claims in respect of any such action or
proceeding may be heard and determined in such Texas State or, to the extent
permitted by law, in such Federal court. Each of the parties hereto agrees that
a final judgment in any such action or proceeding shall be conclusive and may be
enforced in other jurisdictions by suit on the judgment or in any other manner
provided by law. Nothing in this Agreement shall affect any right that the
Administrative Agent or any Lender may otherwise have to bring any action or
proceeding relating to this Agreement against the Borrower or its properties in
the courts of any jurisdiction.

          (c)  The Borrower hereby irrevocably and unconditionally waives, to
the fullest extent it may legally and effectively do so, any objection which it
may now or hereafter have to the laying of venue of any suit, action or
proceeding arising out of or relating to this Agreement in any court referred to
in paragraph (b) of this Section. Each of the parties hereto hereby irrevocably
waives, to the fullest extent permitted by law, the defense of an inconvenient
forum to the maintenance of such action or proceeding in any such court.

          (d)  Each party to this Agreement irrevocably consents to service of
process in the manner provided for notices in Section 10.01. Nothing in this
Agreement will affect the right of any party to this Agreement to serve process
in any other manner permitted by law.

          SECTION 10.10.  WAIVER OF JURY TRIAL.  EACH PARTY HERETO HEREBY
                          --------------------
WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE
TO A TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING OUT OF
OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY (WHETHER
BASED ON CONTRACT, TORT OR ANY OTHER THEORY). EACH PARTY HERETO (A) CERTIFIES
THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED,
EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF
LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER AND (B) ACKNOWLEDGES THAT IT
AND THE OTHER PARTIES HERETO HAVE BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY,
AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION.

          SECTION 10.11.  Headings.  Article and Section headings and the
                          --------
Table of Contents used herein are for convenience of reference only, are not
part of this Agreement and shall not affect the construction of, or be taken
into consideration in interpreting, this Agreement.

                                     -48-
<PAGE>

          SECTION 10.12.  Confidentiality.  Each of the Administrative Agent
                          ---------------
and the Lenders agrees to maintain the confidentiality of the Information (as
defined below), except that Information may be disclosed (a) to its and its
Affiliates' directors, officers, employees and agents, including accountants,
legal counsel and other advisors (it being understood that the Persons to whom
such disclosure is made will be informed of the confidential nature of such
Information and instructed to keep such Information confidential), (b) to the
extent requested by any regulatory authority, (c) to the extent  required by
applicable laws or regulations or by any subpoena or similar legal process, (d)
to any other party to this Agreement, (e) in connection with the exercise of any
remedies hereunder or any suit, action or proceeding relating to this Agreement
or the enforcement of rights hereunder, (f) subject to an executed written
agreement containing provisions substantially the same as those of this Section,
to (i) any actual or prospective assignee of or Participant in any of its rights
or obligations under this Agreement, or (ii) any actual or prospective
counterparty (or its advisors) to any swap or derivative transaction relating to
the Borrower and its obligations, (g) with the written consent of the Borrower
or (h) to the extent such Information (i) becomes publicly available other than
as a result of a breach of this Section or (ii) becomes available to the
Administrative Agent or any Lender on a nonconfidential basis from a source
other than the Borrower or a party to this Agreement.  For the purposes of this
Section, "Information" means all information received from the Borrower relating
          -----------
to the Borrower or its business, other than any such information that is
available to the Administrative Agent or any Lender on a nonconfidential basis
prior to disclosure by the Borrower; provided that, in the case of information
                                     --------
received from the Borrower after the date hereof, such information is clearly
identified at the time of delivery as confidential.

          SECTION 10.13.  Interest Rate Limitation.  Notwithstanding anything
                          ------------------------
herein to the contrary, if at any time the interest rate applicable to any Loan,
together with all fees, charges and other amounts which are treated as interest
on such Loan under applicable law (collectively the "Charges"), shall exceed the
                                                     -------
maximum lawful rate (the "Maximum Rate") which may be contracted for, charged,
                          ------------
taken, received or reserved by the Lender holding such Loan in accordance with
applicable law, the rate of interest payable in respect of such Loan hereunder,
together with all Charges payable in respect thereof, shall be limited to the
Maximum Rate and, to the extent lawful, the interest and Charges that would have
been payable in respect of such Loan but were not payable as a result of the
operation of this Section shall be cumulated and the interest and Charges
payable to such Lender in respect of other Loans or periods shall be increased
(but not above the Maximum Rate therefor) until such cumulated amount, together
with interest thereon at the Federal Funds Effective Rate to the date of
repayment, shall have been received by such Lender.

          SECTION 10.14   UNOCAL.  ADMINISTRATIVE AGENT AND LENDERS ACKNOWLEDGE
                          ------
AND AGREE THAT THEY SHALL HAVE NO CLAIM OR RECOURSE TO UNOCAL OR ANY OF ITS
SUBSIDIARIES (OTHER THAN BORROWER AND ITS RESTRICTED SUBSIDIARIES) IN RESPECT OF
ANY OF THE OBLIGATIONS OR LIABILITIES UNDER ANY OF THE LOAN DOCUMENTS.

          SECTION 10.15   NO ORAL AGREEMENTS.  THE LOAN DOCUMENTS EMBODY THE
                          ------------------
ENTIRE AGREEMENT AND UNDERSTANDING BETWEEN THE PARTIES AND SUPERSEDE ALL OTHER
AGREEMENTS AND UNDERSTANDINGS BETWEEN SUCH PARTIES RELATING TO THE SUBJECT
MATTER HEREOF AND THEREOF.  THE LOAN DOCUMENTS REPRESENT THE FINAL AGREEMENT
BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.  THERE ARE NO
UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

                                     -49-
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed by their respective authorized officers as of the day and year
first above written.


                              PURE RESOURCES, INC.


                              By /s/ William K. White
                                 --------------------

                                      Name:  William K. White
                                      Title: Vice President and
                                             Chief Financial Officer


                     [Credit Agreement - Signature Page 1]
<PAGE>

                              THE CHASE MANHATTAN BANK, individually and
                              as Administrative Agent,



                              By /s/ Robert Traband
                                 ------------------
                                      Name:  Robert Traband
                                      Title: Vice President

                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              The Chase Manhattan Bank
                              One Chase Manhattan Plaza, 8/th/ Floor
                              New York, New York 10081

                              Telecopy No. 212/552-2261
                              Attention: Muniram Appanna


                     [Credit Agreement - Signature Page 2]
<PAGE>

                              FIRST UNION NATIONAL BANK, individually and as
                              Syndication Agent


                              By /s/ Paul N. Riddle
                                 ----------------------------------
                                      Name:  Paul N. Riddle
                                      Title: Senior Vice President

                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              301 South College Street
                              Charlotte, North Carolina 28288

                              Address for Notice:

                              Business/Credit:
                              First Union National Bank
                              1001 Fannin Street, Suite 2255
                              Houston, Texas 77002
                              Telephone No.: 713/346-2717
                              Telecopier No.: 713/650-6354
                              Attention: David E. Humphreys

                              Administrative:
                              First Union National Bank
                              1001 Fannin Street, Suite 2255
                              Houston, Texas 77002
                              Telephone No.: 713/346-2727
                              Telecopier No.: 713/650-6354
                              Attention: Debbie Blank


                     [Credit Agreement - Signature Page 3]
<PAGE>

                              THE BANK OF NEW YORK


                              By /s/ Peter Keller
                                 ------------------------------
                                      Name:  Peter Keller
                                      Title: Vice President


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              The Bank of New York
                              101 Barclay Street
                              New York, New York 10286
                              Attn: Bill Barbiero

                              Address for Notice:

                              Business/Credit:
                              The Bank of New York
                              One Wall Street, 19th Floor
                              New York, New York 10286
                              Telephone No.: 212/635-7861
                              Telecopier No.: 212/635-7923
                              Attn.: Peter Keller

                              Administrative:

                              The Bank of New York
                              One Wall Street, 19th Floor
                              New York, New York 10286
                              Telephone No.: 212/635-7532
                              Telecopier No.: 212/635-7923
                              Attn.: Theresa M. Burke


                     [Credit Agreement - Signature Page 4]
<PAGE>

                              CREDIT LYONNAIS NEW YORK BRANCH


                              By /s/ Philippe Soustra
                                 --------------------
                                      Name:  Philippe Soustra
                                      Title: Senior Vice President


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              Credit Lyonnais New York Branch
                              1301 Avenue of the Americas
                              New York, New York 10019

                              Address for Notice:

                              Business/Credit:
                              Credit Lyonnais
                              1000 Louisiana, Suite 5360
                              Houston, Texas 77002
                              Telephone No.: 713/753-8713
                              Telecopier No.: 713/751-0307
                              Attention: John Grandstaff

                              Administrative:
                              Credit Lyonnais New York Branch
                              1301 Avenue of the Americas
                              New York, New York 10019
                              Telephone No.: 212/261-7633
                              Telecopier No.: 917/849-5440
                              Attention: Bindu Menon


                     [Credit Agreement - Signature Page 5]
<PAGE>

                              BNP PARIBAS, individually and as Documentation
                              Agent

                              By /s/ Brian M. Malone
                                 -------------------------------
                                      Name:  Brian M. Malone
                                      Title: Director

                              By /s/ Betsy Jocher
                                 -------------------------------
                                      Name: Betsy Jocher
                                      Title: Vice President


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              BNP Paribas
                              1200 Smith Street, Suite 3100
                              Houston, Texas 77002

                              Address for Notice:

                              Business/Credit:
                              1200 Smith Street, Suite 3100
                              Houston, Texas 77002
                              Telephone No.: 713/659-4811
                              Telecopier No.: 713/659-6915
                              Attention: Brian Malone

                              Administrative:
                              1200 Smith Street, Suite 3100
                              Houston, Texas 77002
                              Telephone No.: 713/982-1126
                              Telecopier No.: 713/659-5305
                              Attention: Leah Evans Hughes


                     [Credit Agreement - Signature Page 6]
<PAGE>

                              BANK ONE, TEXAS, N.A.


                              By /s/ Wm. Mark Cranmer
                                 ---------------------------------
                                      Name: Wm. Mark Cranmer
                                      Title: Vice President


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              Bank One, Texas, N.A.
                              1717 Main Street, 4/th/ Floor
                              Dallas, Texas 75201

                              Address for Notice:

                              Business/Credit:
                              1717 Main Street, 4/th/ Floor
                              Dallas, Texas 75201
                              Telephone No.: 214/290-2212
                              Telecopier No.: 214/290-2332
                              Attention: Mark Cranmer

                              Administrative:
                              1717 Main Street, 3rd Floor
                              Dallas, Texas 75201
                              Telephone No.: 214/290-2652
                              Telecopier No.: 214/290-2627
                              Attention: Nancy Daniel


                     [Credit Agreement - Signature Page 7]
<PAGE>

                              THE FUJI BANK, LIMITED


                              By /s/ Nate Ellis
                                 -------------------------------------------
                                      Name: Nate Ellis
                                      Title: Senior Vice President & Manager


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              The Fuji Bank, Limited
                              Two World Trade Center
                              New York, New York 70048

                              Address for Notice:

                              Business Credit:
                              The Fuji Bank, Limited
                              One Houston Center
                              1221 McKinney Street, Suite 4100
                              Houston, Texas 77010
                              Telephone No.: 713/759-1800
                              Telecopier No.: 713/759-0717
                              Attention: Mark Polasek

                              Administrative:
                              The Fuji Bank, Limited
                              Two World Trade Center
                              New York, New York 70048
                              Telephone No.: 212/898-2099
                              Telecopier No.: 212/488-8216
                              Attention: Tina Catapano


                     [Credit Agreement - Signature Page 8]
<PAGE>

                              CIBC, INC.


                              By /s/ M. Beth Miller
                                 ---------------------------------
                                      Name: M. Beth Miller
                                      Title: Authorized Signatory


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              CIBC, Inc.
                              2 Paces West
                              2727 Paces Ferry Road, Suite 1200
                              Atlanta, Georgia 30339
                              Attention: Tanya Hunter

                              Address for Notice:

                              Business/Credit:
                              CIBC World Markets
                              1600 Smith Street, Suite 3100
                              Houston, Texas 77002
                              Telephone No.: 713/650-2588
                              Telecopier No.: 713/650-7675
                              Attention: Mack Wolf

                              Administrative:
                              CIBC, Inc.
                              2 Paces West
                              2727 Paces Ferry Road, Suite 1200
                              Atlanta, Georgia 30339
                              Telephone No.: 770/319-4828
                              Telecopier No.: 770/319-4950
                              Attention: Anita Rounds



                     [Credit Agreement - Signature Page 9]
<PAGE>

                              WELLS FARGO BANK (TEXAS), N.A.


                              By /s/ Charles D. Kirkham
                                 ---------------------------------
                                      Name:   Charles D. Kirkham
                                      Title: Vice President


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              Wells Fargo Bank Texas, N.A.
                              1445 Ross Avenue, Suite 200,
                              MAC T 5303 - 029
                              Dallas, Texas 75202

                              Address for Notice:

                              Business/Credit:
                              Wells Fargo Bank Texas, N.A.
                              1445 Ross Avenue, Suite 200,
                              MAC T 5303 - 029
                              Dallas, Texas 75202
                              Telephone No.: 214/777-4026
                              Telecopier No.: 214/303-1839
                              Attention: Charles D. Kirkham

                              Administrative:
                              Wells Fargo Bank, N.A.
                              1740 Broadway
                              Denver, Colorado 80274
                              Telephone No.: 303/863-6102
                              Telecopier No.: 303/863-2729
                              Attention: Tanya Ivie


                    [Credit Agreement - Signature Page 10]
<PAGE>

                              FLEET NATIONAL BANK

                              By /s/ Stephen J. Hoffman
                                 -----------------------------------
                                      Name: Stephen J. Hoffman
                                      Title: Vice President


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              Fleet National Bank
                              100 Federal Street
                              M/C: MADE10008A
                              Boston, Massachusetts 02211


                              Address for Notice:

                              Business/Credit:
                              Fleet National Bank
                              100 Federal Street
                              M/C: MADE10008A
                              Boston, Massachusetts 02211
                              Telephone No.: 617/434-8849
                              Telecopier No.: 617/434-3652
                              Attention: Stephen Hoffman

                              Administrative:
                              Fleet National Bank
                              One Federal Street
                              M/C: MADE1008A
                              Boston, Massachusetts 02211
                              Telephone No.: 617/434-5092
                              Telecopier No.: 617/434-0201
                              Attention: Francia Castillo



                     [Credit Agreement - Signature Page 11]
<PAGE>

                              THE SANWA BANK LIMITED


                              By /s/ Ryoichi Konishi
                                 -------------------------------------
                                      Name: Ryoichi Konishi
                                      Title: Assistant Vice President


                              Lending Office for ABR Loans and
                              Eurodollar Loans:

                              The Sanwa Bank Limited
                              -------------------------------------
                              55 East 52/nd/ Street
                              -------------------------------------
                              New York NY, 10055
                              -------------------------------------

                              Address for Notice:

                              Business/Credit:
                              C. Lawrence Murphy
                              -------------------------------------
                              55 East 52/nd/ Street
                              -------------------------------------
                              New York NY, 10055
                              -------------------------------------
                              Administrative:
                              Priscilla Mark
                              -------------------------------------
                              55 East 52/nd/ Street
                              -------------------------------------
                              New York NY, 10055
                              -------------------------------------



                    [Credit Agreement - Signature Page 12]
<PAGE>

                                                                   SCHEDULE 2.01

                                  COMMITMENTS


             Lender                  Commitment   Percentage Share
             ------                  ----------   ----------------

    The Chase Manhattan Bank       $ 25,000,000      11.904761905%

    First Union National Bank      $ 25,000,000      11.904761905%

           BNP Paribas             $ 25,000,000      11.904761905%

 Credit Lyonnais New York Branch   $ 25,000,000      11.904761905%

      Bank One, Texas, N.A.        $ 25,000,000      11.904761905%

       Fleet National Bank         $ 22,500,000      10.714285714%

      The Bank of New York         $ 12,500,000       5.952380952%

           CIBC, Inc.              $ 12,500,000       5.952380952%

     The Fuji Bank, Limited        $ 12,500,000       5.952380952%

  Wells Fargo Bank Texas, N.A.     $ 12,500,000       5.952380952%

           Sanwa Bank              $ 12,500,000       5.952380952%
                                   ------------     --------------
                   Total:          $210,000,000     100.000000000%

                                      -1-